JP2009115654A - Hydrocarbon concentration measuring instrument, and hydrocarbon concentration measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrocarbon concentration measuring instrument and a hydrocarbon (concentration) measuring method, capable of measuring precisely a concentration of a hydrocarbon with satisfactory responsiveness, even when the concentration and a composition of the hydrocarbon contained in a measuring objective gas vary. <P>SOLUTION: The measuring objective gas is irradiated with a light, having a wavelength band including a common absorption region absorbed by a single or a plurality of chemical species, by an infrared irradiation device 130; the light emitted toward the measuring objective gas is detected by a line sensor 160; absorbance in the common absorption region of the measuring objective gas is calculated by an analyzer 190, based on the detected light; and the sum of the concentrations of the chemical species absorbing the light of the wavelength band in the common absorption region is computed from among the single or plurality of chemical species contained in the measuring objective gas, by the analyzer 190, based on the absorbance. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technique for measuring the concentration of hydrocarbons contained in a gas. More specifically, the present invention relates to an improvement in responsiveness and accuracy of hydrocarbon concentration measurement when the concentration and composition of hydrocarbons contained in a gas change.

In recent years, there has been a demand for further reducing the amount of hydrocarbons contained in the exhaust gas of automobiles and the like due to increasing awareness of environmental issues.
In order to reduce the amount of hydrocarbons contained in the exhaust gas of automobiles, etc., it is necessary to further improve the fuel efficiency of the engine and the exhaust gas purification performance by the catalyst. A technique for accurately measuring the concentration of hydrocarbons contained in a gas is required.

In particular, when performing combustion analysis of the engine, not only when the engine behavior is constant, such as when the engine is running at a constant speed, i.e. when the car is running at a constant speed, but also during the transition period, i.e. when the engine starts or accelerates. -It is necessary to analyze in detail the concentration of hydrocarbons contained in the exhaust gas when the engine behavior changes, such as during deceleration, and the composition (types of chemical species constituting the hydrocarbons and concentrations for each chemical species) is there. However, unlike the stable period, the concentration and composition of hydrocarbons contained in the exhaust gas in the transition period change from moment to moment.
Therefore, the hydrocarbon concentration in the exhaust gas that has high levels of responsiveness to changes in hydrocarbon concentration and composition (that can measure changes in hydrocarbon concentration and composition in real time) and measurement accuracy. Measurement technology is required.

  Conventionally, technologies for measuring the concentration of hydrocarbons contained in gas are classified according to measurement principles. Typical ones are: (1) Flame ionization detector (FID), (2) Non-dispersion A method using a non-dispersive infrared analyzer is known.

(1) The hydrogen flame ionization method is a method of injecting an air-fuel mixture of a gas to be measured and hydrogen gas to be fuel from a nozzle or the like at a predetermined flow rate, and igniting the injected air-fuel mixture. In this method, the ion current of ions is detected by a collector electrode, and the concentration of hydrocarbons contained in the gas to be measured is measured based on the detected ion current.
(1) Examples of the apparatus for measuring the hydrocarbon concentration using the flame ionization method include a total hydrocarbon meter (THC meter) equipped with a flame ionization detector and a gas chromatograph equipped with a flame ionization detector. A gas chromatograph is known.

A total hydrocarbon meter equipped with a flame ionization detector has a flame ionization detector that has an ion current of carbon ions generated by igniting a mixture of a gas to be measured and a hydrogen gas as a fuel. The total hydrocarbon concentration of hydrocarbons contained in the gas to be measured is calculated in the form of a methane concentration converted value (ppmC) based on the detected ion current detected by the collector electrode.
A total hydrocarbon meter equipped with a flame ionization detector is a device that substantially counts the number of carbon atoms contained in the gas to be measured. The composition of each hydrocarbon species contained in the gas cannot be measured.

A gas chromatograph equipped with a flame ionization detector mixes a gas to be measured with a carrier gas (mobile phase), supplies it to a separation column, and separates it for each hydrocarbon species contained in the gas. Each chemical species is mixed with hydrogen gas and ignited, and the ion current of the generated carbon ions is detected by the collector electrode provided in the flame ionization detector and included in the gas to be measured based on the detected ion current The concentration for each chemical species is calculated in the form of a methane concentration conversion value (ppmC).
A gas chromatograph equipped with a flame ionization detector can also calculate the total hydrocarbon concentration of hydrocarbons contained in the gas to be measured by integrating the calculated concentrations for each chemical species.

However, (1) in the hydrocarbon concentration measurement method using the flame ionization method, in general, in order to ensure the measurement accuracy, the measurement conditions, that is, the detection conditions of the ion current by the collector electrode provided in the hydrogen flame ionization detector are constant. Must hold on. Therefore, an operation such as sampling a part of the gas to be measured and performing a pretreatment such as moisture removal is required.
Therefore, there is a time lag between the gas to be measured and the sampled gas (hereinafter referred to as “sampling gas”) for the time required for the pretreatment, that is, a response delay in carbon concentration measurement. There is a problem that it is difficult to measure the concentration of carbon contained in the gas to be measured in real time.

In addition, (1) the hydrocarbon concentration measurement method using the flame ionization method is such that the sampling gas is transferred to a hydrogen flame ionization detector having a collector electrode via a transfer path such as a pipe, so that the inner wall surface of the transfer path, etc. The sampling gas newly supplied to the transport path may be mixed with the old sampling gas remaining in the transport path, and the sampling gas when it reaches the flame ionization detector There is a possibility that the concentration and composition of the hydrocarbons contained may change as compared to the time when the sampling gas is sampled.
Therefore, when the concentration of hydrocarbons contained in the gas to be measured changes from moment to moment, the sampling gas transfer path should be heated or the inner wall surface of the sampling gas transfer path should be coated. This prevents carbon from adhering to the inner wall surface of the transfer path, or the carbon concentration is accurate unless a series of measures such as shortening the transfer path and reducing the amount of sampling gas remaining in the transfer path is performed. There is a problem that it is difficult to measure.

In addition, the gas chromatograph generally has an apparatus configuration in which a sampling gas is supplied to a separation column and separated by time difference for each chemical species constituting the hydrocarbon. It takes a predetermined time (for example, 10 minutes or more).
Therefore, in the gas chromatograph, it is impossible to accurately measure the carbon concentration contained in the gas to be measured in real time.
In addition, gas chromatographs generally have a complicated and large apparatus, and there is a problem that the equipment cost is large as compared with other apparatuses.

(2) The non-dispersive infrared analysis method irradiates a gas to be measured with infrared rays of a predetermined wavelength band, and measures based on absorption of a specific wavelength band of infrared rays irradiated to the gas to be measured. It is the method of measuring the density | concentration of the hydrocarbon contained in the gas used as object.
In principle, the non-dispersive infrared analysis method can measure non-contact hydrocarbon concentration in real time without any delay in response. From the viewpoint of maintaining accuracy, only devices that sample the measurement target gas and perform measurement after pre-processing the same are commercially available in the same manner as the flame ionization method.
(2) A hydrocarbon measuring instrument (HC meter) is known as an example of a hydrocarbon concentration measuring apparatus using a non-dispersive infrared analysis method.

  The hydrocarbon measuring instrument irradiates the gas to be measured with infrared rays in the wavelength band of, for example, around 3.4 μm (3.4 ± 0.07 μm), and the gas to be measured based on the absorption of the infrared rays. Is calculated in the form of a normal hexane concentration conversion value (ppm).

  FIG. 27 shows (a) the measurement result of non-contact measurement of the hydrocarbon concentration in the exhaust gas exhausted from the engine using the infrared absorption method, and (b) a part of the exhaust gas exhausted from the engine. It is a figure which shows the measurement result which measured the density | concentration of the hydrocarbon contained in the gas (sampling gas) using the flame ionization method, and (c) engine speed.

  As shown in FIG. 27, (b) the first rising peak of the measurement result of the hydrocarbon concentration measured using the flame ionization method (represented by a thick dashed line in FIG. 27) is (c) engine rotation It can be seen that there is a response delay due to a delay with respect to the first rising peak of the number (represented by the thick dotted line in FIG. 27).

  On the other hand, (a) the first rising peak of the measurement result of the hydrocarbon concentration measured by non-contact using the infrared absorption method (represented by the thick solid line in FIG. 27) is (c) the first increase in the engine speed. It can be seen that there is no delay with respect to the rising peak, and that there is no response delay such as (b) the measurement result of the hydrocarbon concentration measured using the flame ionization method.

However, (b) the measurement result of the hydrocarbon concentration measured using the flame ionization method once falls after the first rising peak, rises again, and keeps the same value as the peak value of the first rising peak. On the other hand, (a) the measurement result of the hydrocarbon concentration measured by non-contact using the infrared absorption method is substantially the same as the peak value of the first rising peak in (b) with respect to the peak value of the first rising peak. Thereafter, the measured value gradually decreases and shows a value lower than the measured result of (b).
Therefore, even if the influence of the response delay is corrected by shifting the measurement result of (a) in the horizontal axis direction in FIG. 27, the profile is greatly different from the measurement result of (b).

This is because the infrared absorption method used in this test irradiates the gas to be measured with infrared rays of a specific narrow wavelength band (about 3.4 μm) and calculates the concentration of hydrocarbons in the form of normal hexane concentration conversion values. Therefore, it is difficult to accurately measure the hydrocarbon concentration (total hydrocarbon concentration) when the hydrocarbon composition changes greatly as in the exhaust gas during the transition period.
Such a problem also occurs to some extent even in a commercially available HC meter that measures in a wide wavelength range.
An example of a change in the composition of the hydrocarbons contained in the gas is that some of the hydrocarbons contained in the fuel gas are not yet present at the very early stages of engine startup, such as exhaust gas at engine startup. For example, the exhaust gas is discharged together with the exhaust gas as it is burned, and the concentration of hydrocarbons contained in the exhaust gas decreases as the behavior of the engine stabilizes thereafter.

  In this way, it is difficult to achieve both high responsiveness and measurement accuracy in hydrocarbon concentration when the concentration and composition of the hydrocarbon contained in the gas change from moment to moment simply by using the infrared absorption method. It is.

FT-IR (Fourier Transform Infrared Spectrometer) is known as a technique for solving the problem of the change in the hydrocarbon composition.
In addition, a plurality of light projecting units capable of projecting (irradiating) the wavelength absorbed for each chemical species constituting the hydrocarbon to the gas to be measured, and the infrared light projected from each projecting means are received. There is also known a measurement technique that includes a plurality of light receiving units and detects the concentration of each chemical species based on the light reception intensity of each of the plurality of light receiving units. For example, as described in Patent Document 1.

However, FT-IR usually requires sampling of the gas to be measured, poor response, limited types of hydrocarbons (components) that can be measured, and THC measurement. It has the problem of not being.
Moreover, since the technique described in Patent Literature 1 requires the same number of light projecting units and light receiving units as the types of chemical species contained in the gas, there is a problem in that the equipment becomes larger and the equipment cost increases dramatically. There is.
In particular, hydrocarbons contained in the exhaust gas of automobile engines are composed of a large number of chemical species, for example, 200 types or more, and unknown chemical species may be included depending on the fuel composition, combustion conditions, and the like. The above problem becomes significant.
In addition, if the hydrocarbon species contained in the gas to be measured are not accurately known in advance, how many light emitting units and light receiving units need to be provided in the first place, There is a problem that it is not possible to determine how to set the wavelength band of the infrared rays to be emitted (or there is a possibility that chemical species that cannot be measured may appear).
JP-A-4-225142

  In view of the above situation, the present invention measures the hydrocarbon concentration with good responsiveness (in real time) and with high accuracy even when the concentration and composition of the hydrocarbon contained in the gas to be measured change. The present invention provides a hydrocarbon concentration measuring apparatus and a hydrocarbon measuring method that can be used.

  The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.

That is, in claim 1,
An irradiation unit configured to irradiate a gas containing a hydrocarbon composed of one or more chemical species with light in a wavelength band including an absorption region common to the one or more chemical species;
A detection unit for detecting light irradiated to the gas by the irradiation unit;
Analysis that calculates the absorbance of the common absorption region based on the light detected by the detection unit, and calculates the sum of the concentrations of chemical species that absorb light in the wavelength band of the common absorption region based on the absorbance And
It comprises.

In claim 2,
The common absorption region is
It includes a wavelength corresponding to at least one C—H stretching vibration mode of a group consisting of alkane and alkene, a group consisting of aromatic hydrocarbon, and a group consisting of alkyne.

In claim 3,
The wavelength corresponding to the C-H stretching vibration mode of the group consisting of alkanes and alkenes is less 2800 cm ^-1 or 3000 cm ^-1 in terms of wavenumber,
The wavelength corresponding to the C-H stretching vibration mode of the group consisting of aromatic hydrocarbons is below 3000 cm ^-1 or 3200 cm ^-1 in terms of wavenumber,
The wavelength corresponding to the C—H stretching vibration mode of the alkyne group is 3200 cm ⁻¹ or more and 3400 cm ⁻¹ or less in terms of wave number.

In claim 4,
A gas introduction container having an internal space capable of introducing a gas containing hydrocarbons composed of one or a plurality of chemical species, provided in an intermediate portion of an optical path of light irradiated by the irradiation unit and detected by the detection unit; ,
An irradiation side window that is provided in the gas introduction container and transmits the light irradiated by the irradiation unit to the internal space;
A detection-side window that is provided in the gas introduction container and transmits the light guided to the internal space from the irradiation-side window and guides it to the outside;
The gas introduction part provided with is provided.

In claim 5,
Arranged between the irradiation part and the gas containing hydrocarbons composed of one or more chemical species, alternately the state where the light from the irradiation part is irradiated to the gas and the state where the gas is not irradiated A chopper section to be switched,
A signal processing circuit that removes a noise component included in the light detected by the detection unit based on a signal indicating the switching operation of the chopper unit and the light detected by the detection unit;
It comprises.

In claim 6,
The detector is an optical detector;
A spectroscopic unit that divides the light applied to the gas containing hydrocarbons of one or a plurality of chemical species for each wavelength and irradiates the optical detector is provided.

In claim 7,
Irradiation / detection for irradiating a gas containing a hydrocarbon composed of one or more chemical species with light in a wavelength band including an absorption region common to the one or more chemical species, and detecting the light emitted to the gas Process,
The absorbance of the common absorption region is calculated based on the light detected in the irradiation / detection step, and the sum of the concentrations of chemical species that absorb light in the wavelength band of the common absorption region is calculated based on the absorbance. An analysis process to
It comprises.

In claim 8,
The common absorption region is
It includes a wavelength corresponding to at least one C—H stretching vibration mode of a group consisting of alkane and alkene, a group consisting of aromatic hydrocarbon, and a group consisting of alkyne.

In claim 9,
The wavelength corresponding to the C-H stretching vibration mode of the group consisting of alkanes and alkenes is less 2800 cm ^-1 or 3000 cm ^-1 in terms of wavenumber,
The wavelength corresponding to the C-H stretching vibration mode of the group consisting of aromatic hydrocarbons is below 3000 cm ^-1 or 3200 cm ^-1 in terms of wavenumber,
The wavelength corresponding to the C—H stretching vibration mode of the alkyne group is 3200 cm ⁻¹ or more and 3400 cm ⁻¹ or less in terms of wave number.

  The present invention is capable of accurately measuring the concentration and sum of chemical species that absorb light in the wavelength band of the common absorption region in hydrocarbons contained in the gas to be measured. There is an effect.

  The basic principle of the hydrocarbon concentration measuring apparatus according to the present invention and the hydrocarbon concentration measuring method according to the present invention will be described below with reference to FIGS.

The hydrocarbon concentration measuring apparatus according to the present invention is an apparatus for measuring the concentration of hydrocarbons contained in a gas to be measured (hereinafter referred to as “measurement target gas” as appropriate).
The hydrocarbon concentration measurement method according to the present invention is a method for measuring the concentration of hydrocarbons contained in a measurement target gas.

  “Measurement gas” broadly refers to a gas containing hydrocarbons at least in part. Here, the hydrocarbon contained in the measurement target gas is not necessarily vaporized at normal temperature (25 ° C.) and normal pressure (1 atm), and may be vaporized by heating, for example.

“Hydrocarbon” includes one or more chemical species which are compounds composed of carbon and hydrogen. Chemical species contained in hydrocarbons are classified into alkanes, alkenes, alkynes, aromatic hydrocarbons and the like based on their structures.
“Alkane” refers to a chain saturated hydrocarbon represented by the general formula C _n H _{2n + 2} (n: an integer of 1 or more). In the present invention, cycloalkane is included in alkane.
“Cycloalkane” refers to a cyclic saturated hydrocarbon represented by the general formula C _n H _2n (n: an integer of 3 or more).
“Alkene” refers to a chain unsaturated hydrocarbon represented by the general formula C _n H _2n (n: an integer of 2 or more).
“Alkyne” refers to a chain unsaturated hydrocarbon represented by the general formula C _n H _2n-2 (n: an integer of 2 or more).
The “aromatic hydrocarbon” is a hydrocarbon having a single ring or a plurality of ring (fused ring) structures.

  The hydrocarbon concentration measuring apparatus according to the present invention and the hydrocarbon concentration measuring method according to the present invention do not impair “good response (no response delay)” which is an advantage of the conventional non-dispersive infrared analysis method. This solves the problem of the conventional non-dispersive infrared analysis method, “decrease in measurement accuracy when the composition of the gas to be measured (hereinafter referred to as“ measuring gas ”) changes”. .

The hydrocarbon concentration measuring apparatus according to the present invention and the hydrocarbon concentration measuring method according to the present invention irradiate light (infrared rays) on a gas to be measured, and subject to measurement based on absorption (absorbance) of light in a specific wavelength band. The basic principle of measuring the concentration of hydrocarbons contained in the gas is the same as that of the conventional non-dispersive infrared analysis method.
However, the hydrocarbon concentration measuring apparatus according to the present invention and the hydrocarbon concentration measuring method according to the present invention are characterized by a method for setting the wavelength band of light irradiated to the measurement target gas.

  Below, the setting method of the wavelength band of the light irradiated to the measurement object gas in the hydrocarbon concentration measuring apparatus according to the present invention and the hydrocarbon concentration measuring method according to the present invention will be described.

First, the change in the composition of the measurement target gas will be described with reference to FIGS.
FIG. 13A shows an example of a composition analysis result of a fuel supplied to an automobile engine (strictly, a mixture of mist-like fossil fuel and air), and FIG. 14B shows that the fuel is used for an automobile. Example of composition analysis result of exhaust gas (exhaust gas at engine outlet) generated by combustion in engine for engine, FIG. 15 (C) Composition analysis of gas (exhaust gas at catalyst outlet) purified by catalyst An example of the result is shown.
The examples of the composition analysis results (A) to (C) shown in FIGS. 13 to 15 are obtained by a gas chromatograph (FID-GC) using a flame ionization method. In addition, the examples of the composition analysis results (A) to (C) shown in FIG. 13 to FIG. 15 represent the top 26 chemical species having the large calculated compositions.
As shown in FIG. 13 to FIG. 15, when the fuel is burned by the automobile engine and then purified by the catalyst, the types of chemical species, the number of types and the composition of each chemical species contained in the hydrocarbon in the gas at each stage are as follows. It changes a lot.
For example, regarding the number of types of chemical species (total number of chemical species), (A) the total number of chemical species of the air-fuel mixture shown in FIG. 13 is 170, but (B) exhaust gas at the engine outlet shown in FIG. The total number of chemical species increases to 182, and the total number of exhaust gas chemical species at (C) catalyst outlet shown in FIG. 15 decreases to 86.

As for the composition of the chemical species, methane (Methane; denoted by reference numeral (1) in FIG. 14 and FIG. 15) is used as an example, and the composition of (A) the mixture shown in FIG. However, (B) the exhaust gas at the engine outlet and (C) the exhaust gas at the catalyst outlet appear in the top 26 types of the composition.
In particular, in (C) the exhaust gas at the catalyst outlet, methane is the chemical species having the second largest composition among the chemical species contained in the hydrocarbon.

  In addition, the measurement results (A) to (C) are obtained under the condition that the automobile engine used for gas generation is driven at substantially the same load and substantially the same rotational speed. When the driving situation changes (for example, driving situation corresponding to starting, idling, acceleration, deceleration, running on a hill, etc. in actual driving), the hydrocarbons included in the gases (A) to (C) are configured. The type of chemical species, the number of types, and the composition of each chemical species vary greatly.

  Of the hydrocarbon species contained in the gas shown in FIGS. 13 to 15, the absorption spectra of 24 species having a large composition are different as shown in FIGS. The wavelength band where the absorbance is large is also different.

Accordingly, the gas shown in FIG. 13 to FIG. 15 is used as a measurement target gas, and using a conventional non-dispersive infrared analysis method, for example, a very narrow specific wavelength band near 3.4 μm (2941 cm ⁻¹ in terms of wave number) is used. When the total hydrocarbon concentration is calculated based on the light absorption, there are many chemical species that do not have an absorption region in the specific wavelength band, so the measurement accuracy of the total hydrocarbon concentration is high. It can be said that it is natural.

  The hydrocarbon concentration measuring apparatus according to the present invention and the hydrocarbon concentration measuring method according to the present invention include (a) a group consisting of an alkane and an alkene. b) A group consisting of aromatic hydrocarbons and (c) a group consisting of alkynes, and by setting a “common absorption region” for each group, the sum of the concentrations of chemical species belonging to each group Is calculated with high accuracy.

  The above three groups (a) to (c) are classified based on the difference in structure of chemical species belonging to each group, more strictly, on the difference in bonding state between a plurality of carbon atoms contained in the chemical species. ing.

  (A) Among the chemical species belonging to the group consisting of alkane and alkene, the plurality of carbon atoms constituting the alkane have at least one single bond with another carbon atom, and the plurality of carbon atoms constituting the alkene Any one of them has one double bond with another carbon atom. Of the alkanes, methane is an exception because it contains only one carbon atom.

  (B) Examples of the chemical species belonging to the group consisting of aromatic hydrocarbons include a group of cyclic unsaturated hydrocarbons represented by benzene.

  (C) In the chemical species belonging to the group consisting of alkynes, any of the plurality of carbon atoms constituting the chemical species has one triple bond with another carbon atom.

Absorption of light (infrared rays) by hydrocarbons occurs due to stretching vibration (CH stretching mode) of bonds between carbon atoms and hydrogen atoms constituting chemical species contained in hydrocarbons.
Normally, the absorption of light by the C-H stretching vibration mode takes place in a wavelength band near ^{2850cm -1 ~2960cm} -1 in terms of wavenumber, and actually a plurality of carbon atoms and other atoms constituting the species Since the bonding state (geometric structure) of each species differs depending on the chemical species, even if the same type of bond (single bond, double bond, triple bond), the bonding state between multiple carbon atoms is different for each chemical species. Slightly different.
As a result, the bonding state between the carbon atom and the hydrogen atom constituting the chemical species is slightly changed due to the influence of the bonding state between the plurality of carbon atoms, and light absorption is caused by the C—H stretching vibration for each chemical species. wavelength band occurs, i.e. the absorption region slightly varies from the wavelength band near ^{2850cm -1 ~2960cm} -1 in terms of wavenumber. This is why the absorption spectrum profile, peak wavelength, or absorbance differs for each chemical species.

However, the chemical species shown in FIGS. 16 to 23 are divided into three groups: (a) a group consisting of alkane and alkene, (b) a group consisting of aromatic hydrocarbons, and (c) a group consisting of alkynes. looking at, (a) alkanes and the absorption region of the chemical species belonging to the group consisting of alkene wavelength range is below 3.571μm or 3.333μm (2800cm ^-1 or 3000 cm ^-1 or less in the range in terms of wavenumber) to have roughly subsided, (b) 3000 cm ^-1 or 3200 cm ^-1 or less absorption region of the chemical species belonging to the group consisting of aromatic hydrocarbons wavelength in terms of 3.333μm following range (wavenumber than 3.125μm (C) the absorption region of the chemical species belonging to the group consisting of alkynes has a wavelength of 2.941. 3.125μm following range of m can be seen that roughly fall (in terms of wavenumber 3200 cm ^-1 or 3400 cm ^-1 following range).

Therefore, "common absorption region where the chemical species belonging to the group consisting of alkanes and alkenes absorb light" 2800 cm ^-1 or 3000 cm ^-1 following the waveband, in terms of wavenumber, 3000 cm ^-1 or more, in terms of wavenumber 3200 cm ^- A wavelength band of ¹ or less is “a common absorption region that is absorbed by a chemical species belonging to a group consisting of aromatic hydrocarbons”, and a waveband of 3200 cm ⁻¹ or more and 3400 cm ⁻¹ or less is converted to a wave number “ Absorbance of “common absorption region absorbed by the chemical species belonging to the group consisting of alkane and alkene” and (a) belonging to the group consisting of alkane and alkene Relation to the sum of the composition of chemical species, (B) the relationship between the absorbance of the "common absorption region absorbed by" and (b) the sum of the composition of the chemical species belonging to the group consisting of aromatic hydrocarbons, and the "common absorption region absorbed by the chemical species belonging to the group consisting of alkynes" ”And (c) the sum of the composition of chemical species belonging to each of the alkyne groups, the results shown in FIG. 25 and FIG. 26 were obtained.

FIG. 25 shows (B) exhaust gas at the engine outlet (see FIG. 14) and (C) exhaust gas at the catalyst outlet (see FIG. 15). “PpmC composition ratio” and “IR-Abs. Ratio” when divided into three groups: a group consisting of alkane and alkene, (b) a group consisting of aromatic hydrocarbons, and (c) a group consisting of alkynes. , Are compared.
Here, the “12 chemical species” are specifically selected from the 24 chemical species shown in FIGS. 13 to 15 (1) Methane, (5) i-Pentane, (6) n-Pentane, (13) Ethylene, (14) Propylene, (15) i-Butene, (16) 1-Butene, (17) Benzen, (18) Toluene, (19) m-Xylene, (21) p- Xylene, (24) refers to Acetylene.

“Methane concentration conversion value (ppmC)” is represented by the product of the concentration (ppm) of a chemical species and the carbon number of the chemical species ([ppmC] = [ppm] × [carbon number of chemical species]). It is the value which converted the density | concentration of the seed | species into the methane density | concentration of the same number as the carbon atom contained in the said chemical species.
For example, when the concentration of ethane is 100 ppm, the number of carbon atoms in ethane is 2, so the ethane concentration conversion value of ethane is 200 (= 100 × 2) ppmC.

  “PpmC composition ratio” is the sum of the methane concentration conversion values of the chemical species belonging to each group when the sum of the methane concentration conversion values of all the chemical species constituting the hydrocarbon contained in the measurement target gas is 100% ( %).

  The “IR-Abs. Ratio” is calculated by the procedure shown in FIG.

First, by standardizing the absorption spectrum data of each chemical species into data per unit concentration and unit measurement length, for each chemical species, (a) a common chemical species that belongs to the group consisting of alkane and alkene is absorbed. Absorbance per unit concentration in the absorption region, (b) Absorbance per unit concentration in the common absorption region absorbed by chemical species belonging to the group consisting of aromatic hydrocarbons, and (c) Chemical species belonging to the group consisting of alkynes The absorbance per unit concentration in the common absorption region to be absorbed is calculated. The absorbance per unit concentration is referred to as “unit absorbance”. Here, “measurement length” refers to the length at which the measurement target gas and the light used for measurement intersect.
“Unit absorbance” is α _{(a)-(1) to} α _(a)-(16) , α _{(b)-(17) to} α _(b)-(23) , α _(c) -in FIG. ₍₂₄₎ , β _{(a)-(1) to} β _(a)-(16) , β _{(b)-(17) to} β _(b)-(23) , β _(c)-(24) , γ _{It corresponds to (a)-(1) to} γ _(a)-(16) , γ _{(b)-(17) to} γ _(b)-(23) , γ _(c)-(24) .

Next, for each chemical species, “absorbance in each absorption region” is calculated as the product of the concentration (ppm) of the chemical species and the unit absorbance of the chemical species previously calculated.
“Absorptivity in each absorption region” is expressed as α _(a)-(1) · C _{1 to} α _(a)-(16) · C ₁₆ , α _(b)-(17) · C _{17 to} α _{(b in FIG. )-(23)} · C ₂₃ , α _(c)-(24) · C ₂₄ , β _(a)-(1) · C _{1 to} β _(a)-(16) · C ₁₆ , β _{(b)- (17)} · C _{17 to} β _(b)-(23) · C ₂₃ , γ _(c)-(24) · C ₂₄

Subsequently, using the calculated “absorbance in each region for each chemical species”, the sum of the absorbance in the absorption region corresponding to the chemical species of the chemical species belonging to the same group is calculated.
(A) The absorbance sum of the chemical species belonging to the group consisting of alkane and alkene is the absorbance sum of (a) in FIG. 24 (= α _{(a) − (1)} · C ₁ +... + Α _{(a) − ( 16)} · corresponds to C ₁₆ ).
(B) The absorbance sum of the chemical species belonging to the group consisting of aromatic hydrocarbons is the absorbance sum of (b) in FIG. 24 (= β _{(b) − (17)} · C ₁₇ +... + Β _{(b) − (23)} · C ₂₃ ).
(C) The absorbance sum of the chemical species belonging to the group consisting of alkynes corresponds to the absorbance sum (= γ _{(c) − (24)} · C ₂₄ ) in FIG.

Subsequently, the calculated (a) sum of absorbances of chemical species belonging to the group consisting of alkane and alkene, (b) sum of absorbances of chemical species belonging to the group consisting of aromatic hydrocarbons, and (c) belonging to the group consisting of alkynes Calculate the sum of the absorbance of the chemical species.
As a ratio (%) of the absorbance sum of chemical species belonging to the group consisting of (a) alkane and alkene, (IR) Ab-Abs. Calculate the ratio.
Similarly, the IR-Abs. Ratio and IR-Abs. Calculate the ratio.

  As shown in FIG. 25, the composition ratio sum (ppmC composition ratio) based on FID-GC and the IR-Abs of each group, despite comparison of some of a large number of chemical species (12 species). . The ratio shows a relatively good agreement.

FIG. 26 shows (B) exhaust gas at the engine outlet (see FIG. 14) and (C) exhaust gas at the catalyst outlet (see FIG. 15), for a total of 24 chemical species (FIG. 16 to FIG. 16) contained in these gases. All chemical species whose absorption spectra are shown in FIG. 23 are divided into three groups: (a) a group consisting of alkanes and alkenes, (b) a group consisting of aromatic hydrocarbons, and (c) a group consisting of alkynes. "PpmC composition ratio" and "IR-Abs. Ratio" are compared.
The sum of the volumes of the 24 chemical species is about 75% when (B) exhaust gas at the engine outlet is 100%, and (C) exhaust gas at the catalyst outlet is It is about 65% when the sum of the volume of chemical species is 100%.
As shown in FIG. 26, compared with FIG. 25 shown above, the number of target chemical species increased from 12 to 24, the sum of the composition ratios based on FID-GC (ppmC composition ratio) and each group IR-Abs. The ratio shows a better agreement.

  Thus, the hydrocarbons contained in the gas to be measured are divided into three groups: (a) a group consisting of alkanes and alkenes, (b) a group consisting of aromatic hydrocarbons, and (c) a group consisting of alkynes. When “a common absorption region” is set for each, the knowledge that the sum of the concentrations of the chemical species belonging to each group can be accurately measured based on the absorbance of the absorption region is obtained.

  Based on the above knowledge, the hydrocarbon concentration measuring device according to the present invention and the hydrocarbon concentration measuring method according to the present invention convert the hydrocarbon contained in the measurement target gas into the structure of the chemical species constituting the hydrocarbon (between atoms). It is divided into three groups based on the bonding state), and the sum of the composition of the chemical species belonging to each group (the sum of the concentrations) is measured with good responsiveness and accuracy.

  Hereinafter, a hydrocarbon concentration measuring apparatus 100 as a first embodiment of the hydrocarbon concentration measuring apparatus according to the present invention will be described with reference to FIGS. 1 to 5.

The hydrocarbon concentration measuring apparatus 100 measures the concentration of hydrocarbons contained in the measurement target gas.
As shown in FIG. 1, the hydrocarbon concentration measuring device 100 mainly includes an optical rail 110, a gas introducing unit 120, an infrared irradiation device 130, a chopper device 140, a lens 151, a diffraction grating 152, a line sensor 160, a sensor control device 170, and signal processing. A circuit 180, an analysis device 190, and the like are included.

  The optical rail 110 is a main structure of the hydrocarbon concentration measuring device 100, and a group of optical systems of the hydrocarbon concentration measuring device 100 (infrared irradiation device 130, chopper device 140, lens 151, diffraction grating 152, line sensor 160, etc. ) Is attached.

The gas introduction unit 120 is an embodiment of the gas introduction unit according to the present invention, and includes a gas introduction container 121, an irradiation side window 122, a detection side window 123, and the like.
The gas introduction container 121 is a substantially cylindrical member having flanges formed at both ends, and has an internal space 121a therein. The measurement target gas is introduced into the internal space 121 a of the gas introduction container 121 by interposing the gas introduction container 121 in the middle of the conveyance path for conveying the measurement target gas.
The irradiation side window 122 and the detection side window 123 are windows provided in the gas introduction container 121. In this embodiment, transparent quartz or the like is fitted into a hole penetrating the outer peripheral surface and the inner peripheral surface of the gas introduction container 121. Is formed.
The gas introduction unit 120 is provided in the middle of the optical path through which the light irradiated by the infrared irradiation device 130 is detected by the line sensor 160. The position and posture of the gas introduction unit 120 are the irradiation side window 122 and the detection side. The window 123 is adjusted so as to intersect the optical path.

  In addition, although the gas introduction part 120 of a present Example was set as the structure which forms the irradiation side window 122 and the detection side window 123 by mounting transparent quartz etc. in the gas introduction container 121, this invention is limited to this. First, for example, a substantially cylindrical container is provided with a pair of holes penetrating from the inner peripheral surface to the outer peripheral surface, and optical fibers are respectively fitted into the pair of holes. It is good also as a structure which fulfill | performs "the function as an optical path from the said container" and "the function as a detection side window, and the function as an optical path from the said container to a detection part."

The gas introduction part 120 is provided with means (heater or the like) for heating each member (gas introduction container 121, irradiation side window 122, detection side window 123, etc.) constituting the gas introduction part 120. It is desirable to keep each member to be above a predetermined temperature.
By holding each member constituting the gas introduction part 120 at a predetermined temperature or higher, contamination of the optical system due to adhesion of chemical species constituting the hydrocarbon contained in the measurement target gas and aggregation of moisture is prevented. As a result, it is possible to ensure the accuracy of the hydrocarbon concentration measurement by the hydrocarbon concentration measuring apparatus 100.

The infrared irradiation device 130 is an embodiment of the irradiation unit according to the present invention, and a chemical species belonging to the group consisting of (a) alkane and alkene is added to the measurement target gas introduced into the internal space 121a of the gas introduction container 121. A common absorption region to be absorbed, (b) a common absorption region to be absorbed by a chemical species belonging to the group consisting of aromatic hydrocarbons, and (c) a common absorption region to be absorbed by a chemical species belonging to the group consisting of alkynes. Irradiates light in a wavelength band including.
Light (infrared rays) emitted from the infrared irradiation device 130 passes through the irradiation side window 122 of the gas introduction unit 120, is guided to the internal space 121a of the gas introduction container 121, and is irradiated to the measurement target gas introduced into the internal space 121a. Is done. The light irradiated to the measurement target gas passes through the detection-side window 123 of the gas introduction unit 120 and is guided to the outside of the gas introduction unit 120.
Infrared radiator 130 of this embodiment includes a semiconductor device capable of generating infrared radiation including a wavelength range 2800 cm ^-1 or 3400 cm ^-1 following in terms of wavenumber, for example, an IR element.
In this embodiment, the wavelength band of light (infrared) to the infrared radiator 130 irradiates the measurement target gas is less 2000 cm ^-1 or 4000 cm ^-1 in terms of wavenumber, the group (a) consisting of alkanes and alkenes (B) common absorption region absorbed by chemical species belonging to the group consisting of aromatic hydrocarbons, (c) common absorption region absorbed by chemical species belonging to the group consisting of alkynes Includes all absorption areas.

The chopper device 140 is an embodiment of the chopper unit according to the present invention, and (i) a state in which light from the infrared irradiation device 130 is irradiated to the measurement target gas introduced into the internal space 121a of the gas introduction unit 120 (light The state in which the measurement target gas is irradiated and the state in which the measurement target gas is not irradiated (the state where the light is blocked) are alternately switched to periodically change the intensity of light irradiated to the measurement target gas. (Modulate). The chopper device 140 is disposed between the infrared irradiation device 130 and the gas introduction unit 120 (more strictly, a measurement target gas).
The chopper device 140 mainly includes a motor 141, a turntable 142, a chopper control device 143, and the like.

  The motor 141 is an electric motor, and its drive shaft is fixed to the center of the rotating disk 142.

  The rotating disk 142 is a substantially disk-shaped member, and a plurality of holes penetrating the front and back surfaces of the disk surface are formed on the disk surface. The plurality of holes formed in the turntable 142 are arranged with a predetermined regularity in the circumferential direction of the turntable 142. The turntable 142 is made of a material that does not transmit light emitted by the infrared irradiation device 130.

The turntable 142 is disposed at a position that intersects the optical path of the light emitted from the infrared irradiation device 130 between the infrared irradiation device 130 and the gas introduction unit 120 (more strictly, the measurement target gas).
When the motor 141 is driven to rotate, the rotating plate 142 rotates, and a state where any of the plurality of holes formed in the rotating plate 142 intersects the optical path and a portion other than the hole formed in the rotating plate 142 intersects the optical path. The state switches alternately.

In a state where the hole formed in the turntable 142 intersects the optical path, the light emitted from the infrared irradiation device 130 passes through the hole formed in the turntable 142 and is introduced into the internal space 121a of the gas introduction unit 120. The measurement target gas is irradiated.
In a state where the part other than the hole formed in the turntable 142 intersects the optical path, the light to be irradiated from the infrared irradiation device 130 is blocked by the turntable 142 and introduced into the internal space 121a of the gas introduction unit 120. The gas is not irradiated.

The chopper control device 143 controls the rotation of the motor 141 and its stop, and the number of rotations of the motor 141 (and hence the number of rotations of the turntable 142), and is a programmable program storing a program for controlling the operation of the motor 141. It consists of a controller (Programmable Logic Controller; PLC).
The chopper control device 143 is connected to the motor 141 and transmits a signal (control signal) for controlling the rotation speed of the motor 141 to the motor 141.
Further, the chopper control device 143 outputs a signal indicating the switching operation of the chopper device 140 as a reference signal.
The reference signal is output when the turntable 142 is in a predetermined phase. The cycle in which the reference signal is output is from (i) the state in which the measurement target gas introduced into the internal space 121a of the gas introduction unit 120 is irradiated with light from the infrared irradiation device 130 (ii) the state in which the measurement target gas is not irradiated This corresponds to (i) the time required to switch to the state in which the measurement target gas introduced into the internal space 121a of the gas introduction unit 120 is irradiated again.

  The chopper device 140 of the present embodiment crosses a rotating plate 142 formed with a plurality of holes in the middle of the optical path, and the rotating plate 142 rotates to pass or block light and chop the light (light However, the chop portion according to the present invention is not limited to this, and a plurality of slits (grooves) are provided. It is good also as a structure which passes or interrupts | blocks light and the light is chopped by rotating the formed turntable. In addition, a configuration in which light is chopped using an electro-optic element or the like can be another embodiment of the chop portion according to the present invention.

  The lens 151 converges (squeezes) light guided through the detection-side window 123 of the gas introduction unit 120 and guided to the outside of the gas introduction unit 120. Note that the lens 151 may be omitted when light transmitted through the detection-side window 123 of the gas introduction unit 120 and guided to the outside of the gas introduction unit 120 has sufficient intensity.

The diffraction grating 152 is an embodiment of the spectroscopic unit according to the present invention, and divides the light converged by the lens 151 for each wavelength by diffraction and irradiates the line sensor 160.
The diffraction grating 152 is made of a metal plate in which a number of grooves parallel to each other (about several thousand per 1 mm) are formed on a mirror-finished surface. The light incident on the diffraction grating 152 is diffracted and dispersed for each wavelength, and the dispersed light is irradiated to the line sensor 160 at different reflection angles depending on the wavelength.
Note that the diffraction grating 152 of the present embodiment is configured by a metal plate having a number of grooves parallel to each other on the surface, but the spectroscopic unit according to the present invention is not limited to this, and incident light is separated for each wavelength. Other configurations may be used as long as they are spectroscopic.
Other embodiments of the spectroscopic unit according to the present invention include a diffraction grating having a large number of parallel slits and a prism (which performs spectroscopic analysis using the refractive index of the medium).

The line sensor 160 is an embodiment of the detection unit according to the present invention, and detects light irradiated to the measurement target gas by the infrared irradiation device 130.
The line sensor 160 includes a plurality of light receiving elements (pixels) that receive light (infrared rays) arranged in a line. A positional relationship (attitude) between the lattice 152 and the line sensor 160 is determined.

In the case of this embodiment, the line sensor 160 has a pixel No. No. 1-No. A total of 200 light receiving elements (pixels) up to 200 are arranged in a line.
Among the light receiving elements constituting the line sensor 160, No. 83-No. 117 of the light receiving element, in terms of wavenumber 2800 cm ^-1 or 3000 cm ^-1 or less in the wavelength band, i.e. corresponding to the "common absorption region where the group absorbs consisting of alkanes and alkenes".
Among the light receiving elements constituting the line sensor 160, No. 118-No. 0.99 3000 cm ^-1 or 3200 cm ^-1 or less in the wavelength band light receiving elements, in terms of wavenumber, that corresponds to the "common absorption region where the chemical species absorbs belonging to the group consisting of aromatic hydrocarbons".
Among the light receiving elements constituting the line sensor 160, No. 151-No. The light receiving elements up to 184 correspond to a wavelength band of 3200 cm ⁻¹ or more and 3400 cm ⁻¹ or less in terms of wave number, that is, “a common absorption region absorbed by chemical species belonging to the group consisting of alkynes”.
It should be noted that the total pixel sweep frequency (No. 1 → 200) of the line sensor 160 in this embodiment is sufficiently higher than the optical chopping frequency by the rotary plate 142 and the chopper controller 143 (light ON / OFF). It is desirable that the chopping frequency is twice or more, more preferably several tens of times or more when measured in OFF). Alternatively, the total pixel sweep frequency (No. 1 → 200) of the line sensor 160 in this embodiment is sufficiently lower than the optical chopping frequency by the above-described rotating plate 142 and chopper controller 143 (desirably, the chopping frequency). It is desirable that it should be less than one hundredth of the above.
Further, the line sensor 160 of the present embodiment has a configuration in which a plurality of light receiving elements are arranged in a line, but the detection unit according to the present invention is not limited to this. Other configurations of the detection unit according to the present invention include a configuration composed of a single light receiving element, a configuration composed of a plurality of light receiving elements, and the like.

The sensor control device 170 controls the operation of the line sensor 160, and includes a programmable controller (PLC) in which a program for controlling the operation of the line sensor 160 is stored.
The sensor control device 170 acquires (receives) a light reception intensity signal that is information related to the light reception intensity of each of the plurality of light receiving elements (pixels) included in the line sensor 160 from the line sensor 160. In the case of the present embodiment, the received light intensity signal is an electrical signal having a voltage substantially proportional to the received light intensity of the light received by each light receiving element.
Each of the plurality of light receiving elements included in the line sensor 160 has a unique number (light receiving element number) set in advance, and the sensor control device 170 transmits a light reception intensity signal to the signal processing circuit 180 in the order of the light receiving element numbers.
In addition, the sensor control device 170 analyzes a signal (pixel No. signal) indicating which one of the plurality of light receiving elements of the line sensor 160 corresponds to the received light intensity signal transmitted to the signal processing circuit 180. To device 190.

The signal processing circuit 180 removes noise from the received light intensity signal acquired from the sensor control device 170.
The signal processing circuit 180 is connected to the chopper device 140 and acquires (receives) a reference signal from the chopper device 140.
The signal processing circuit 180 is connected to the sensor control device 170 and acquires (receives) a received light intensity signal from the sensor control device 170.
Based on the reference signal and the received light intensity signal, the signal processing circuit 180 extracts “a component synchronized with a periodic intensity change” in the received light intensity signal, thereby removing a noise component included in the received light intensity signal.
The signal processing circuit 180 transmits the received light intensity signal from which the noise component has been removed to the analysis device 190. The signal processing circuit 180 removes noise from the received light intensity signal, so that the resolution of the received light intensity signal is improved, and a minute change (or a minute hydrocarbon concentration) of the hydrocarbon concentration can be measured more accurately. is there.
The signal processing circuit 180 of the present embodiment may be a dedicated product, but may be achieved using a commercially available signal processing circuit.

The analysis device 190 is an embodiment of the analysis unit according to the present invention. Based on the light detected by the line sensor 160, “a common absorption region absorbed by chemical species belonging to each group” for the measurement target gas. Is calculated, and the sum of the concentrations of the chemical species belonging to the groups respectively corresponding to these absorption regions is calculated.
The analysis device 190 mainly includes an analysis unit 191, an input unit 192, a display unit 193, and the like.

  The analysis unit 191 stores various programs and the like (for example, an absorbance calculation program and a concentration calculation program described later), expands these programs and the like, performs predetermined calculations according to these programs, and outputs the calculation results and the like. Can be remembered.

The analysis unit 191 may actually have a configuration in which a CPU, a ROM, a RAM, an HDD, and the like are connected by a bus, or may be configured by a one-chip LSI or the like.
The analysis unit 191 of this embodiment is a dedicated product, but it can also be achieved by storing the above-described program in a commercially available personal computer, workstation or the like.

The analysis unit 191 is connected to the sensor control device 170, and the pixel No. It is possible to acquire (receive) a signal.
The analysis unit 191 is connected to the signal processing circuit 180 and can acquire (receive) a received light intensity signal (more precisely, a noise component is removed).

The input unit 192 is connected to the analysis unit 191 and inputs various information / instructions related to the analysis by the hydrocarbon concentration measuring apparatus 100 to the analysis unit 191.
Although the input unit 192 of the present embodiment is a dedicated product, the same effect can be achieved by using a commercially available keyboard, mouse, pointing device, button, switch, or the like.

The display unit 193 displays input contents from the input unit 192 to the analysis unit 191, analysis results (measurement results of hydrocarbon concentration) by the analysis unit 191, and the like.
Although the display unit 193 of this embodiment is a dedicated product, the same effect can be achieved even if a commercially available monitor, liquid crystal display, or the like is used.

Below, the detailed structure of the analysis part 191 is demonstrated.
The analysis unit 191 functionally includes a storage unit 191a, an absorbance calculation unit 191b, a concentration calculation unit 191c, and the like.

  The storage unit 191 a stores information used for various calculations performed in the analysis unit 191, calculation results, and the like.

The storage unit 191a stores a spectrum of a reference gas (hereinafter referred to as a reference gas).
The “reference gas” is a gas that is known in advance not to absorb light in the three absorption regions of hydrocarbons contained in the measurement target gas. A specific example of the reference gas is nitrogen gas.
The “reference gas spectrum” indicates the relationship between the wavelength and the light intensity when the reference gas is irradiated with light.
In this embodiment, the wavelength band of the spectrum of the reference gas is set in a range of 2000 cm ^-1 or 4000 cm ^-1 or less in terms of wavenumber. This is to set the range including all the absorption regions of the three groups of hydrocarbons.

The spectrum of the reference gas is acquired prior to the measurement (i) periodically (for example, once a month) or (ii) every time the hydrocarbon concentration is measured by the hydrocarbon concentration measuring apparatus 100. It is desirable to update by
By appropriately updating the spectrum of the reference gas, contamination of the optical system such as the irradiation side window 122, the detection side window 123, and the lens 151, deterioration of the semiconductor element of the infrared irradiation device 130, deterioration of the light receiving element of the line sensor 160, optical path It is possible to prevent a decrease in measurement accuracy due to deterioration of a filter (not shown) that intersects with.

The absorbance calculation unit 191b calculates the absorbance of the common absorption region of the measurement target gas based on the light detected by the line sensor 160.
Substantially, the analysis unit 191 performs a predetermined calculation or the like according to the absorbance calculation program, thereby functioning as the absorbance calculation unit 191b.

The absorbance calculation unit 191b receives the pixel number from the sensor control device 170. A signal is acquired and a received light intensity signal is acquired from the signal processing circuit 180.
Pixel No. acquired from the sensor control device 170. The signal is substantially information representing the geometric positional relationship between the corresponding light receiving element and the diffraction grating 152, that is, the diffraction angle of light by the diffraction grating 152, and consequently the wavelength of the light received by the corresponding light receiving element. Is information.
Therefore, the absorbance calculation unit 191b uses the pixel No. By collating the signal with the received light intensity signal, it is possible to specify the wavelength (wavelength band) corresponding to the acquired received light intensity signal.

  The absorbance calculation unit 191b is configured to absorb the chemical species belonging to the group consisting of “alkane and alkene” of the measurement target gas based on “the received light intensity signal with the specified wavelength (wavelength band)” and “the spectrum of the reference gas”. Absorbance in the absorption region ”,“ Absorbance in the common absorption region absorbed by chemical species belonging to the group consisting of aromatic hydrocarbons ”and“ Absorbance in the common absorption region absorbed by chemical species belonging to the group consisting of alkynes ” Calculate each.

More specifically, the absorbance calculation unit 191b determines whether the pixel No. No. 83-No. From the sum of the received light intensity signals corresponding to the light receiving elements up to 117, “the received light intensity of the common absorption region absorbed by the chemical species belonging to the group consisting of alkane and alkene” is calculated.
In addition, the absorbance calculation unit 191b includes the pixel No. No. 118-No. From the sum of the received light intensity signals corresponding to up to 150 light receiving elements, “the received light intensity of the common absorption region absorbed by the chemical species belonging to the group consisting of aromatic hydrocarbons” is calculated.
In addition, the absorbance calculation unit 191b includes the pixel No. No. 151-No. From the sum of the received light intensity signals corresponding to the light receiving elements up to 184, “the received light intensity of the common absorption region absorbed by the chemical species belonging to the alkyne group” is calculated.

Next, the absorbance calculation unit 191b calculates the “received light intensity of the common absorption region absorbed by the chemical species belonging to the group consisting of alkane and alkene” and “the group consisting of alkane and alkene in the reference gas spectrum”. Based on the intensity of light in the wavelength band corresponding to the common absorption region absorbed by the chemical species to which it belongs, "absorbance of the common absorption region absorbed by the chemical species belonging to the group consisting of alkane and alkene" for the measurement target gas Is calculated.
Similarly, the absorbance calculation unit 191b performs “absorbance of a common absorption region absorbed by chemical species belonging to the group consisting of aromatic hydrocarbons” and “chemical species belonging to the group consisting of alkynes” for the measurement target gas. The absorbance of the common absorption region ”is calculated.

  “Absorbance of a common absorption region absorbed by chemical species belonging to the group consisting of alkanes and alkenes”, “Absorbance of common absorption region absorbed by chemical species belonging to the group consisting of aromatic hydrocarbons” for the measurement target gas, The calculation of “absorbance of a common absorption region absorbed by chemical species belonging to the group consisting of alkynes” is performed using the following equation (1).

In Equation 1, An refers to absorbance, and In refers to the intensity of light transmitted through the absorption wavelength region of interest when the measurement target gas is irradiated with light (transmitted light received intensity; hereinafter referred to as “received light intensity”). (In) ₀ indicates the intensity of light transmitted through the absorption wavelength region of interest when the reference gas (generally containing no hydrocarbons) is irradiated with light.

The concentration calculation unit 191c determines whether the chemical species belonging to the group consisting of alkane and alkene is based on “absorbance of the common absorption region absorbed by the chemical species belonging to the group consisting of alkane and alkene” calculated by the absorbance calculation unit 191b. "Sum of concentrations" is calculated, and "Sum of concentrations of chemical species belonging to group consisting of aromatic hydrocarbons" is calculated based on "absorbance of common absorption region absorbed by chemical species belonging to groups consisting of aromatic hydrocarbons" And “the sum of the concentrations of chemical species belonging to the group consisting of alkynes” is calculated based on “absorbance of the common absorption region absorbed by chemical species belonging to the group consisting of alkynes”.
Substantially, the analysis unit 191 functions as the concentration calculation unit 191c by performing a predetermined calculation or the like according to the concentration calculation program.

Specifically, the concentration calculation unit 191c calculates the product of the coefficient A stored in advance in the storage unit 191a and “absorbance of a common absorption region absorbed by chemical species belonging to the group consisting of alkane and alkene”. The “sum of concentrations of chemical species belonging to the group consisting of alkane and alkene” contained in the gas is calculated.
Similarly, the concentration calculation unit 191c calculates the gas to be measured as the product of the coefficient B stored in advance in the storage unit 191a and “absorbance of a common absorption region absorbed by chemical species belonging to the group consisting of aromatic hydrocarbons”. The “sum of the concentrations of chemical species belonging to the group consisting of aromatic hydrocarbons” included in is calculated.
Similarly, the concentration calculation unit 191c is included in the measurement target gas as the product of the coefficient C stored in advance in the storage unit 191a and the “absorbance of the common absorption region absorbed by the chemical species belonging to the alkyne group”. The “sum of the concentrations of chemical species belonging to the group consisting of alkynes” is calculated.

  Further, the concentration calculation unit 191c calculates the “sum of concentrations of chemical species belonging to the group consisting of alkane and alkene”, “sum of concentrations of chemical species belonging to the group consisting of aromatic hydrocarbons”, and “alkynes” calculated above. As the sum of the “sum of the concentrations of the chemical species belonging to the group consisting of”, the “total hydrocarbon concentration of the measurement target gas” is calculated.

Note that the coefficient A, coefficient B, and coefficient C stored in advance in the storage unit 191a are the amount of light (light quantity) irradiated by the infrared irradiation device 130, the measurement length (in the case of this embodiment, the gas introduction unit 120). Gas corresponding to the distance from the irradiation-side window 122 to the detection-side window 123), etc., and the hydrocarbon concentration measuring apparatus 100 detects a gas whose hydrocarbon composition is known in advance by FID-GC or the like. Calculation result of “absorbance of common absorption region absorbed by chemical species belonging to group consisting of alkane and alkene”, “common absorption region absorbed by chemical species belonging to group consisting of aromatic hydrocarbons” Experimentally determined based on the calculation result of "absorbance" and the calculation result of "absorbance of a common absorption region absorbed by chemical species belonging to the group consisting of alkynes". That.
In this embodiment, the sum of the concentrations of the chemical species belonging to each group and the total hydrocarbon concentration calculated by the concentration calculation unit 191c are calculated in the form of methane equivalent concentration values (ppmC). Is not limited to this, and may be calculated in the form of a volume ratio or the like.

  Hereinafter, an example of a hydrocarbon concentration measurement experiment using the hydrocarbon concentration measuring apparatus 100 will be described with reference to FIGS. 2 to 5.

As shown in FIG. 2, an example of a hydrocarbon concentration measurement experiment by the hydrocarbon concentration measuring apparatus 100 is performed using the experimental facility 1.
The experimental equipment 1 includes a hydrocarbon concentration measuring device 100, an engine 2, an engine control device 3, a main exhaust passage 4, a sub exhaust passage 5, a GC analysis gas bag 6, a valve 7, a sub exhaust passage 8, a pretreatment device 9, and a valve. 10, a pump 11, a THC meter 12, a valve 13, a sub exhaust path 14, a valve 15, and the like.

The engine 2 generates exhaust gas that is a measurement target gas in this experiment.
The engine control device 3 is connected to the engine 2 and controls an operation state such as the rotational speed of the engine 2.

  One end of the main exhaust path 4 is connected to the exhaust manifold of the engine 2 and the other end is connected to an exhaust treatment device (not shown) that removes particulates and hydrocarbons in the exhaust gas and releases the remaining gas to the atmosphere. It consists of piping connected in communication with the device. Most of the exhaust gas generated in the engine 2 is sent to the exhaust treatment device through the main exhaust path 4.

  The hydrocarbon concentration measuring device 100 is provided in the middle of the main exhaust path 4. More precisely, the gas introduction part 120 of the hydrocarbon concentration measuring apparatus 100 is interposed in the middle part of the main exhaust path 4, and the exhaust gas passes through the internal space 121a of the gas introduction part 120 (gas introduction container 121).

  The auxiliary exhaust path 5 is connected in communication with a position (a position close to the engine 2) whose one end is in the middle of the main exhaust path 4 and upstream of the gas introduction section 120, and the other end is connected to an exhaust processing device (not shown). It consists of piping connected in communication.

  The GC analysis gas bag 6 is a container (or bag) for collecting exhaust gas, and the collected exhaust gas is subjected to composition analysis by a GC (gas chromatograph) (not shown). The GC analysis gas bag 6 is provided in the middle of the auxiliary exhaust path 5.

  The valve 7 is provided at a position in the middle of the auxiliary exhaust path 5 and upstream of the GC analysis gas bag 6 (position close to the engine 2). When the valve 7 is opened, a part of the exhaust gas that passes through the main exhaust passage 4 passes through the GC analysis gas bag 6. When the valve 7 is closed, the exhaust gas passing through the main exhaust path 4 does not pass through the GC analysis gas bag 6.

  The auxiliary exhaust path 8 is connected in communication with a position (a position far from the engine 2) whose one end is in the middle of the main exhaust path 4 and downstream of the gas introduction section 120, and the other end is connected to an exhaust processing device (not shown). It consists of piping connected in communication.

  The pretreatment device 9 removes particulates (dust) and moisture contained in the exhaust gas, and is a combination of a filter for trapping particulates, a desiccant, and the like. The pretreatment device 9 is provided in the middle of the sub exhaust path 8.

  The valve 10 is provided at a position in the middle of the sub exhaust path 8 and upstream of the pretreatment device 9 (position close to the engine 2). When the valve 10 is opened, a part of the exhaust gas passing through the main exhaust passage 4 passes through the pretreatment device 9. When the valve 10 is closed, the exhaust gas passing through the main exhaust path 4 does not pass through the pretreatment device 9.

  The pump 11 is provided at a position in the middle of the auxiliary exhaust path 8 and downstream of the pretreatment device 9 (position far from the engine 2). The pump 11 sucks exhaust gas from a port on the main exhaust path 4 side of the sub exhaust path 8 and exhausts it from a port on the exhaust processing device side (not shown) of the sub exhaust path 8, thereby exhaust gas to the sub exhaust path 8. Promote the inflow of

  The THC meter 12 is a device that measures the total hydrocarbon concentration by a flame ionization method (FID). The THC meter 12 may be a dedicated product, but may be achieved with a commercially available THC meter or the like.

  The valve 13 is provided at a position downstream of the pump 11 and upstream of the THC meter 12 in the middle portion of the auxiliary exhaust path 8. When the valve 13 is opened, the exhaust gas passing through the pretreatment device 9 and the pump 11 passes through the THC meter 12. When the valve 13 is closed, the exhaust gas that has passed through the pretreatment device 9 and the pump 11 does not pass through the THC meter 12.

  One end of the sub exhaust path 14 is connected to a position downstream of the pump 11 and upstream of the valve 13 in the middle of the sub exhaust path 8, and the other end is connected to an exhaust processing apparatus (not shown). Made of piping.

  The valve 15 is provided in the middle of the auxiliary exhaust path 14. When the valve 15 is opened, a part of the exhaust gas that has passed through the pretreatment device 9 and the pump 11 passes through the auxiliary exhaust path 14. When the valve 15 is closed, the exhaust gas that has passed through the pretreatment device 9 and the pump 11 does not pass through the sub exhaust path 14.

  Below, the procedure and experimental result of the hydrocarbon concentration measurement experiment by the hydrocarbon concentration measuring apparatus 100 will be described.

  The hydrocarbon concentration measurement experiment by the hydrocarbon concentration measuring apparatus 100 is divided into two parts: (1) a response confirmation experiment, and (2) a measurement accuracy confirmation experiment when the engine is in steady operation. Will be described in order.

Hereinafter, the procedure of (1) responsiveness confirmation experiment will be described.
First, the engine 2 is started with the valve 7, the valve 10, the valve 13 and the valve 15 closed, and the engine 2 is set to an idling state.
Next, when the rotational speed of the engine 2 is stabilized in the idling state, the valve 10, the valve 13 and the valve 15 are opened, and the hydrocarbon concentration measurement by the hydrocarbon concentration measuring device 100 and the hydrocarbon concentration measurement by the THC meter 12 are started. .
Subsequently, after the hydrocarbon concentration measurement by the hydrocarbon concentration measuring apparatus 100 and the hydrocarbon concentration measurement by the THC meter 12 are started, the rotational speed of the engine 2 is increased to a predetermined rotational speed after a lapse of a predetermined time.
Subsequently, after increasing the rotational speed of the engine 2 to a predetermined rotational speed, the engine 2 is stopped after a predetermined time has elapsed, and the hydrocarbon concentration measurement by the hydrocarbon concentration measuring device 100 and the hydrocarbon concentration measurement by the THC meter 12 are performed. finish.

As shown in FIG. 3, the measurement result of the total hydrocarbon concentration by the THC meter 12 (indicated by a thick dotted line in FIG. 3) shows that the total hydrocarbon concentration increases after a few seconds have elapsed since the increase in the rotational speed of the engine 2. The response delay is happening.
On the other hand, the measurement result of the total hydrocarbon concentration by the hydrocarbon concentration measuring apparatus 100 (shown by a thick solid line in FIG. 3) shows that the total hydrocarbon concentration is increased simultaneously with the increase in the rotational speed of the engine 2. No response delay has occurred.
Therefore, it can be seen that the hydrocarbon concentration measuring apparatus 100 has high responsiveness in measuring the hydrocarbon concentration.
Further, in the measurement result of the total hydrocarbon concentration by the THC meter 12, the change in the total hydrocarbon concentration is smooth due to the response delay, and it is difficult to capture a minute concentration change.
On the other hand, the measurement result of the total hydrocarbon concentration by the hydrocarbon concentration measuring apparatus 100 captures even a minute change in the total hydrocarbon concentration immediately after the increase in the total hydrocarbon concentration as shown in FIG.

Hereinafter, (2) the procedure of the measurement accuracy confirmation experiment when the engine is in steady operation will be described.
First, the engine 2 is started with the valve 7, the valve 10, the valve 13 and the valve 15 closed, and the engine 2 is set to a predetermined rotational speed.
Next, when the rotational speed of the engine 2 is stabilized at a predetermined rotational speed, the valve 7, the valve 10, the valve 13 and the valve 15 are opened, the hydrocarbon concentration measurement by the hydrocarbon concentration measuring device 100 and the hydrocarbon by the THC meter 12. Concentration measurement is started and collection of each chemical species by the GC analysis gas bag 6 is started.
Subsequently, the hydrocarbon concentration measurement by the hydrocarbon concentration measuring device 100, the hydrocarbon concentration measurement by the THC meter 12, and the collection of each chemical species by the gas bag for GC analysis 6 are started, and the hydrocarbon concentration after a lapse of a predetermined time. The hydrocarbon concentration measurement by the measuring device 100, the hydrocarbon concentration measurement by the THC meter 12, and the collection of each chemical species by the GC analysis gas bag 6 are finished, and then the engine 2 is stopped.
(2) In the measurement accuracy confirmation experiment when the engine is in steady operation, a total of four experimental conditions are obtained by changing the “predetermined number of revolutions” of the engine and the concentration (composition) of the fuel supplied to the engine. The experiment was conducted for each experimental condition.

4 and 5 are diagrams showing experimental results of a measurement accuracy confirmation experiment when (2) the engine is in steady operation.
In FIG. 4A, the measurement result of the total hydrocarbon concentration by the THC meter 12 is taken as the horizontal axis (X axis), and the measurement result of the total hydrocarbon concentration by the hydrocarbon concentration measuring device 100 measured under the same experimental conditions is shown in the vertical axis. Plotted as an axis (Y axis).
FIG. 4B shows the “concentration of chemical species belonging to the group consisting of alkanes and alkenes” calculated from the concentration measurement results by GC of each chemical species collected by the GC analysis gas bag 6 on the horizontal axis ( X axis), and the measurement result of “concentration of chemical species belonging to the group consisting of alkane and alkene” by the hydrocarbon concentration measuring apparatus 100 measured under the same experimental conditions is plotted as the vertical axis (Y axis). .
(A) in FIG. 5 shows the “concentration sum of chemical species belonging to the group consisting of aromatic hydrocarbons” calculated from the concentration measurement result by GC of each chemical species collected by the gas bag 6 for GC analysis. (X-axis) plotted with the vertical axis (Y-axis) of the measurement result of “concentration of chemical species belonging to the group consisting of aromatic hydrocarbons” by the hydrocarbon concentration measuring apparatus 100 measured under the same experimental conditions It is.
(B) in FIG. 5 shows the “concentration of chemical species belonging to the group consisting of alkynes” calculated from the concentration measurement result by GC of each chemical species collected by the GC analysis gas bag 6 on the horizontal axis (X-axis). ) And the measurement result of “concentration of chemical species belonging to the group consisting of alkynes” by the hydrocarbon concentration measuring apparatus 100 measured under the same experimental conditions is plotted as a vertical axis (Y axis).

As shown in FIGS. 4 and 5, the sum of the total hydrocarbon concentration and the concentration of the chemical species belonging to each group is plotted in the vicinity of the straight line Y = X.
Accordingly, the measurement results of “total hydrocarbon concentration” and “sum of the concentrations of chemical species belonging to each group” by the hydrocarbon concentration measuring apparatus 100 are respectively the corresponding “measurement result of total hydrocarbon concentration by THC meter 12” and It shows a good agreement with the “sum of concentrations of chemical species belonging to each group calculated from the concentration measurement result by GC”.

As described above, the hydrocarbon concentration measuring apparatus 100 is
Light in a wavelength band including an absorption region common to one or a plurality of chemical species in a measurement target gas (a gas containing a hydrocarbon composed of one or a plurality of chemical species) (in this example, 2000 cm in terms of wave number) ^{-1 to} 4000 cm ⁻¹ (light in a wavelength band),
A line sensor 160 that detects light irradiated to the measurement target gas by the infrared irradiation device 130;
Based on the light detected by the line sensor 160, the absorbance of the common absorption region of the measurement target gas is calculated, and the chemical species that absorbs light in the wavelength band of the common absorption region based on the absorbance (that is, the common absorption) An analysis device 190 that calculates the sum of the concentrations of the chemical species belonging to the group corresponding to the region;
It comprises.
By configuring in this way, there is no delay in response to changes in the concentration and composition of the gas to be measured, and it is possible to measure hydrocarbon concentration in real time, ensuring measurement responsiveness. It is.
In addition, when the concentration or composition of the gas to be measured changes, the sum of the concentrations of chemical species that absorb light in the common absorption region (that is, chemical species belonging to the group corresponding to the common absorption region) is accurately calculated. Is possible.

In this example, the sum of the concentrations of chemical species was calculated for each of (a) a group consisting of alkane and alkene, (b) a group consisting of aromatic hydrocarbons, and (c) a group consisting of alkynes. The total hydrocarbon concentration is calculated as the sum of the calculation results, but the present invention is not limited to this, and (a) a group consisting of alkanes and alkenes, (b) a group consisting of aromatic hydrocarbons, (c) Among the group consisting of alkynes, the target gas is irradiated with light having a wavelength including an absorption region corresponding to a part of the group, and chemical species belonging to the corresponding group are detected based on the absorbance of the detected light in the absorption region. It may be configured to calculate only the sum of the densities.
An example of this is light that includes an absorption region corresponding to a group of aromatic hydrocarbons, when it is desired to measure only the concentration of aromatic hydrocarbons whose exhaust gas concentration is desired to be low in consideration of the environment. The exhaust gas is irradiated and the sum of the concentrations of chemical species belonging to the group consisting of aromatic hydrocarbons is calculated based on the absorbance of the detected light in the absorption region.

Further, the common absorption region included in the light irradiated by the infrared irradiation device 130 of the hydrocarbon concentration measuring device 100 is:
The wavelength corresponding to the C—H stretching vibration mode of the chemical species group consisting of (a) alkane and alkene, (b) the chemical species group consisting of aromatic hydrocarbons, and (c) the chemical species group consisting of alkynes, respectively. Is included.
By configuring in this way, it is possible to measure the sum of the concentrations of the chemical species belonging to each of the above groups with good responsiveness and accuracy.
In the present embodiment, the measurement target gas is irradiated with light in a wavelength band that includes all absorption regions corresponding to the three groups. However, the present invention is not limited to this, and any of the above three groups may be used. It is good also as a structure which irradiates the measurement object gas with the light containing the wavelength corresponding to CH stretching mode of any one or any two groups, and measures the sum of the density | concentration of the chemical species which belongs to a corresponding group.

The hydrocarbon concentration measuring device 100 is
(A) a wavelength corresponding to a C-H stretching vibration mode of the group consisting of alkanes and alkenes is less 2800 cm ^-1 or 3000 cm ^-1 in terms of wavenumber,
(B) a wavelength corresponding to a C-H stretching vibration mode of the group consisting of aromatic hydrocarbons is below 3000 cm ^-1 or 3200 cm ^-1 in terms of wavenumber,
(C) The wavelength corresponding to the C—H stretching vibration mode of the group consisting of alkynes is 3200 cm ⁻¹ or more and 3400 cm ⁻¹ or less in terms of wave number.
By configuring in this way, it is possible to measure the sum of the concentrations of the chemical species belonging to each of the above groups with good responsiveness and accuracy.

The hydrocarbon concentration measuring device 100 is
A gas introduction container 121 having an internal space 121a provided in the middle of the optical path of the light irradiated by the infrared irradiation device 130 and detected by the line sensor 160;
An irradiation-side window 122 that is provided in the gas introduction container 121 and transmits the light irradiated by the infrared irradiation device 130 to the internal space 121a;
A detection-side window 123 that is provided in the gas introduction container 121 and transmits the light guided from the irradiation-side window 122 to the internal space 121a and guides it to the outside;
The gas introduction part 120 provided with is provided.
By configuring in this way, there is no response delay with respect to changes in the concentration and composition of the measurement target gas introduced into the gas introduction unit 120, and it is possible to measure the hydrocarbon concentration in real time. It is possible to ensure responsiveness.
In addition, when the concentration or composition of the gas to be measured changes, the sum of the concentrations of chemical species that absorb light in the common absorption region (that is, chemical species belonging to the group corresponding to the common absorption region) is accurately calculated. Is possible.

The hydrocarbon concentration measuring device 100 is
A chopper device 140 that is arranged between the infrared irradiation device 130 and the measurement target gas, and alternately switches between a state in which the light from the infrared irradiation device 130 is irradiated on the measurement target gas and a state in which the gas is not irradiated on the measurement target gas;
A signal processing circuit 180 for removing a noise component included in the light detected by the line sensor 160 based on a signal (reference signal) indicating the switching operation of the chopper device 140 and the light detected by the line sensor 160;
It comprises.
With such a configuration, the resolution of the intensity of light detected by the line sensor 160 is improved, and consequently the measurement accuracy of the hydrocarbon concentration is improved.

Moreover, the detection part (detecting the light irradiated to measurement object gas) of the hydrocarbon concentration measuring apparatus 100 is the line sensor 160,
The hydrocarbon concentration measuring apparatus 100 includes a diffraction grating 152 that divides the light applied to the measurement target gas and irradiates the line sensor 160 with the light.
With this configuration, it is possible to detect light in a desired absorption region with a simple configuration.
Further, it is possible to simultaneously detect light in a plurality of absorption regions, which contributes to improvement in responsiveness of carbon concentration measurement.
Furthermore, increasing the number of pixels of the line sensor 160 improves the wavelength resolution of the detected light, contributing to an improvement in measurement accuracy.

In addition, the absorbance calculation unit 191b of the hydrocarbon concentration measuring apparatus 100 is
Of the light detected by the line sensor 160, the light absorbance detected by the line sensor 160 is corrected based on the intensity of light in a wavelength band (correction region) where absorption by hydrocarbons contained in the measurement target gas does not occur. Is.
By configuring in this way, it is possible to prevent a decrease in the accuracy of the hydrocarbon concentration measurement due to a change in the amount of light.

  Hereinafter, a hydrocarbon concentration measuring apparatus 200 as a second embodiment of the hydrocarbon concentration measuring apparatus according to the present invention will be described with reference to FIG.

The hydrocarbon concentration measuring apparatus 200 measures the concentration of hydrocarbons contained in the measurement target gas.
As shown in FIG. 6, the hydrocarbon concentration measuring apparatus 200 mainly includes an optical rail 210, a gas introducing part 220 including a gas introducing container 221, an irradiation side window 222 and a detection side window 223, an infrared irradiation apparatus 230, a motor 241 and a rotating disk. , And a chopper control device 243, a lens 251, a diffraction grating 252, photodiodes 260, 260..., A signal switching device 270, a signal processing circuit 280, an analysis device 290, and the like.

  Among the members constituting the hydrocarbon concentration measuring apparatus 200, the optical rail 210, the gas introducing unit 220, the infrared irradiation apparatus 230, the chopper apparatus 240, the lens 251, and the diffraction grating 252 are each shown in FIG. The optical rail 110, the gas introduction unit 120, the infrared irradiation device 130, the chopper device 140, the lens 151, and the diffraction grating 152 in FIG.

The photodiodes 260, 260... Are an embodiment of the detection unit according to the present invention, and detect light irradiated to the measurement target gas by the infrared irradiation device 230.
The photodiode 260 is an element that generates an electric signal (light reception intensity signal) corresponding to the intensity of the received light, and is diffracted so that the light divided by the diffraction grating 252 is irradiated to different photodiodes 260. A positional relationship (attitude) between the grating 252 and the photodiodes 260, 260... Is determined.

The signal switching device 270 is connected to the photodiodes 260, 260..., And acquires the received light intensity signals from the photodiodes 260, 260.
The signal switching device 270 sequentially selects (switches) the received light intensity signal of any one of the photodiodes 260 among the received light intensity signals for each of the acquired photodiodes 260, 260. To 280. At this time, the signal switching frequency needs to be set sufficiently lower than the optical chopping frequency by the rotary plate 242 and the chopper controller 243 described above (desirably, tens of times the optical chopping frequency).
Further, the signal switching device 270 transmits a signal (light receiving element No. signal) indicating to which one of the photodiodes 260, 260... The received light intensity signal transmitted to the signal processing circuit 280 corresponds to the analyzing device 290. To do.

The signal processing circuit 280 removes noise from the received light intensity signal acquired from the signal switching device 270.
The signal processing circuit 280 is connected to the chopper device 240 and acquires (receives) a reference signal from the chopper device 240.
The signal processing circuit 280 is connected to the signal switching device 270 and acquires (receives) the received light intensity signal from the signal switching device 270.
Based on the reference signal and the received light intensity signal, the signal processing circuit 280 extracts the “component synchronized with the periodic intensity change” in the received light intensity signal, thereby removing the noise component contained in the received light intensity signal.
The signal processing circuit 280 transmits the received light intensity signal from which the noise component has been removed to the analysis device 290. The signal processing circuit 280 removes noise from the received light intensity signal, thereby improving the resolution of the received light intensity signal and making it possible to measure a minute change in hydrocarbon concentration (or minute hydrocarbon concentration) with higher accuracy. It is.

The analysis device 290 is an embodiment of the analysis unit according to the present invention. Based on the light detected by the photodiodes 260, 260,..., “The chemical species belonging to each group absorbs the measurement target gas. The absorbance of the “common absorption region” is calculated, and the sum of the concentrations of the chemical species belonging to the groups respectively corresponding to these absorption regions is calculated.
The analysis device 290 mainly includes an analysis unit 291, an input unit 292, a display unit 293, and the like.

  The analysis unit 291 stores various programs and the like (for example, an absorbance calculation program and a concentration calculation program described later), expands these programs and the like, performs predetermined calculations according to these programs and the like, and outputs the calculation results and the like. Can be remembered.

The analysis unit 291 may actually have a configuration in which a CPU, a ROM, a RAM, an HDD, and the like are connected by a bus, or may be configured by a one-chip LSI or the like.
The analysis unit 291 of the present embodiment is a dedicated product, but it can also be achieved by storing the above-described program in a commercially available personal computer or workstation.

The analysis unit 291 is connected to the signal switching device 270, and the light receiving element No. It is possible to acquire (receive) a signal.
The analysis unit 291 is connected to the signal processing circuit 280, and can acquire (receive) a received light intensity signal (more precisely, a noise component is removed).

  The configuration of the input unit 292 and the display unit 293 is substantially the same as that of the input unit 192 and the display unit 193 shown in FIG.

Below, the detailed structure of the analysis part 291 is demonstrated.
The analysis unit 291 functionally includes a storage unit 291a, an absorbance calculation unit 291b, a concentration calculation unit 291c, and the like.

  The storage unit 291a stores information used for various calculations performed in the analysis unit 291 and calculation results.

The storage unit 291a stores a spectrum of the reference gas.
The method for acquiring the reference gas spectrum is substantially the same as the hydrocarbon concentration measuring apparatus 100 shown in FIG.

The absorbance calculation unit 291b calculates the absorbance of a common absorption region of the measurement target gas based on the light detected by the photodiodes 260, 260.
Substantially, the analysis unit 291 performs a predetermined calculation or the like in accordance with the absorbance calculation program, thereby functioning as the absorbance calculation unit 291b.

The absorbance calculation unit 291b receives the light receiving element No. from the signal switching device 270. A signal is acquired and a received light intensity signal is acquired from the signal processing circuit 280.
The light receiving element No. acquired from the signal switching device 270. The signal is substantially information representing the geometric positional relationship between the corresponding photodiode 260 and the diffraction grating 252, that is, the diffraction angle of light by the diffraction grating 252, and thus light received by the corresponding photodiode 260. It is the information showing the wavelength.
Therefore, the absorbance calculation unit 291b receives the light receiving element No. By collating the signal with the received light intensity signal, it is possible to specify the wavelength (wavelength band) corresponding to the acquired received light intensity signal.

  The absorbance calculating unit 291b is configured to absorb the chemical species belonging to the group consisting of “alkane and alkene” of the measurement target gas based on “the received light intensity signal whose wavelength (wavelength band) is specified” and “the spectrum of the reference gas”. Absorbance in the absorption region ”,“ Absorbance in the common absorption region absorbed by chemical species belonging to the group consisting of aromatic hydrocarbons ”and“ Absorbance in the common absorption region absorbed by chemical species belonging to the group consisting of alkynes ” Calculate each.

More specifically, the absorbance calculation section 291b is of the "wavelength light reception intensity signal (wavelength band) is identified," received light intensity signal corresponding to, in terms of wavenumber 2800 cm ^-1 or 3000 cm ^-1 or less in the wavelength band From this sum, “the light receiving intensity of the common absorption region absorbed by the chemical species belonging to the group consisting of alkane and alkene” is calculated.
Further, the absorbance calculation section 291b is the sum of the received-light-intensity-signal corresponding to one wavelength band 3000 cm ^-1 or 3200 cm ^-1 following in terms of wavenumber of "wavelength light reception intensity signal (wavelength band) is identified,"" The light receiving intensity of a common absorption region absorbed by chemical species belonging to the group consisting of aromatic hydrocarbons is calculated.
In addition, the absorbance calculation unit 291b converts the wave number from the sum of the received light intensity signals corresponding to the wavelength band of 3200 cm ⁻¹ or more and 3400 cm ⁻¹ or less in the “received light intensity signal whose wavelength (wavelength band) is specified”. The light receiving intensity of a common absorption region absorbed by chemical species belonging to the group consisting of alkynes is calculated.

Next, the absorbance calculation unit 291b calculates the “light-receiving intensity of the common absorption region absorbed by the chemical species belonging to the group consisting of alkane and alkene” and “the group consisting of alkane and alkene in the reference gas spectrum”. Based on the intensity of light in the wavelength band corresponding to the common absorption region absorbed by the chemical species to which it belongs, “absorbance of the common absorption region absorbed by the chemical species belonging to the group consisting of alkane and alkene” for the measurement gas Is calculated.
Similarly, the absorbance calculation unit 291b performs “absorbance of a common absorption region absorbed by chemical species belonging to the group consisting of aromatic hydrocarbons” and “chemical species belonging to the group consisting of alkynes” for the measurement target gas. The absorbance of the common absorption region ”is calculated.

  “Absorbance of a common absorption region absorbed by chemical species belonging to the group consisting of alkanes and alkenes”, “Absorbance of common absorption region absorbed by chemical species belonging to the group consisting of aromatic hydrocarbons” for the measurement target gas, The calculation of “absorbance of a common absorption region absorbed by a chemical species belonging to the group consisting of alkynes” is performed using Equation 1 above.

The concentration calculation unit 291c determines whether the chemical species belonging to the group consisting of alkane and alkene is calculated based on the “absorbance of the common absorption region absorbed by the chemical species belonging to the group consisting of alkane and alkene” calculated by the absorbance calculation unit 291b. "Sum of concentrations" is calculated, and "Sum of concentrations of chemical species belonging to group consisting of aromatic hydrocarbons" is calculated based on "absorbance of common absorption region absorbed by chemical species belonging to groups consisting of aromatic hydrocarbons" And “the sum of the concentrations of chemical species belonging to the group consisting of alkynes” is calculated based on “absorbance of the common absorption region absorbed by chemical species belonging to the group consisting of alkynes”.
Substantially, the analysis unit 291 performs a function such as a concentration calculation unit 291c by performing a predetermined calculation or the like according to the concentration calculation program.
The configuration of the concentration calculation unit 291c is substantially the same as that of the concentration calculation unit 191c shown in FIG.

As described above, the hydrocarbon concentration measuring apparatus 200 is
Light in a wavelength band that includes a common absorption region that is absorbed by one or more chemical species in the gas to be measured (a gas containing hydrocarbons of one or more chemical species) (in this example, converted to wave number) the infrared radiator 230 which irradiates the 2000 cm ^-1 or 4000 cm ^-1 the following waveband light) Te,
Photodiodes 260, 260,... For detecting light irradiated to the measurement target gas by the infrared irradiation device 230;
Based on the light detected by the photodiodes 260, 260..., The absorbance of a common absorption region of the measurement target gas is calculated, and based on the absorbance, common among one or more chemical species included in the measurement target gas An analyzer 290 that calculates the sum of the concentrations of chemical species that absorb light in the wavelength band of the absorption region (that is, chemical species that belong to a group corresponding to a common absorption region);
It comprises.
By configuring in this way, there is no delay in response to changes in the concentration and composition of the gas to be measured, and it is possible to measure hydrocarbon concentration in real time, ensuring measurement responsiveness. It is.
In addition, when the concentration or composition of the gas to be measured changes, the sum of the concentrations of chemical species that absorb light in the common absorption region (that is, chemical species belonging to the group corresponding to the common absorption region) is accurately calculated. Is possible.

Moreover, the detection part (detecting the light irradiated to measurement object gas) of the hydrocarbon concentration measuring apparatus 200 is a plurality of photodiodes 260, 260.
The hydrocarbon concentration measuring apparatus 200 includes a diffraction grating 252 that divides the light applied to the measurement target gas and irradiates the photodiodes 260, 260,.
With this configuration, it is possible to detect light in a desired absorption region with a simple configuration.
Further, it is possible to simultaneously detect light in a plurality of absorption regions, which contributes to improvement in responsiveness of carbon concentration measurement.

In the present embodiment, the received light intensity signal corresponding to one of the photodiodes 260 is selected by the signal switching device 270 from the received light intensity signals acquired from the plurality of photodiodes 260, 260. Although it is configured to input to the processing circuit 280, the same number of signal processing circuits as a plurality of photodiodes are prepared, the signal switching device is omitted, and the received light intensity signal from each photodiode is input to the corresponding signal processing circuit It is also possible.
In such a configuration, the time lag caused by the time required for switching the output signal by the signal switching device is eliminated, so that the responsiveness of the hydrocarbon concentration measurement is further improved.

  In this embodiment, the light is detected by a plurality of photodiodes 260, 260,..., But a single photodiode is moved relative to the diffraction grating to change the wavelength of the single photodiode. It is also possible to adopt a configuration for detecting band light. In such a configuration, since light is received by a single photodiode, it is not possible to simultaneously detect light in a plurality of “common absorption regions”.

  Hereinafter, a hydrocarbon concentration measuring apparatus 300 as a third embodiment of the hydrocarbon concentration measuring apparatus according to the present invention will be described with reference to FIG.

The hydrocarbon concentration measuring apparatus 300 measures the concentration of hydrocarbons contained in the measurement target gas.
As shown in FIG. 7, the hydrocarbon concentration measuring apparatus 300 mainly includes an optical rail 310, a gas introducing section 320 including a gas introducing container 321, an irradiation side window 322, and a detection side window 323, an infrared irradiation apparatus 330, a motor 341 and a rotating disk. A chopper device 340 including a 342 and a chopper control device 343, a lens 351, a photodiode 360, a filter switching device 370, a signal processing circuit 380, an analysis device 390, and the like are provided.

  Among the members constituting the hydrocarbon concentration measuring apparatus 300, the optical rail 310, the gas introducing unit 320, the infrared irradiation apparatus 330, the chopper apparatus 340, and the lens 351 are respectively optical rails in the hydrocarbon concentration measuring apparatus 100 shown in FIG. 110, the gas introduction unit 120, the infrared irradiation device 130, the chopper device 140, and the lens 151 have substantially the same configuration, and thus detailed description thereof is omitted.

The photodiode 360 is an embodiment of the detection unit according to the present invention, and detects light irradiated to the measurement target gas by the infrared irradiation device 330.
The photodiode 360 is a semiconductor element that generates an electrical signal (light reception intensity signal) corresponding to the intensity of received light.

The filter switching device 370 is provided in the middle of the optical path of the light irradiated by the infrared irradiation device 330, and switches the wavelength band of the light detected by the photodiode 360 out of the light.
The filter switching device 370 mainly includes a motor 371, a filter board 372, a filter control device 373, and the like.

  The motor 371 is an electric motor, and its drive shaft is fixed to the center of the filter panel 372.

  The filter board 372 is a substantially disk-shaped member, and a total of five holes are formed through the front and back surfaces of the board surface. The five holes formed in the filter board 372 are arranged at equal intervals in the circumferential direction of the filter board 372. The filter panel 372 is made of a material that does not transmit the light irradiated by the infrared irradiation device 330.

Of the five holes formed in the filter disc 372, the one hole, in terms of wavenumber 2800 cm ^-1 or 3000 cm ^-1 or less in the wavelength band (common where the chemical species belonging to the group consisting of alkanes and alkenes absorb light bandpass filter 372a which transmits light absorption region), one of 3000 cm ^-1 or more, in terms of wavenumber in the hole 3200 cm ^-1 or less in the wavelength band (common where the chemical species belonging to the group consisting of aromatic hydrocarbons absorb A bandpass filter 372b that transmits light in an absorption region), and a wavelength band of 3200 cm ⁻¹ or more and 3400 cm ⁻¹ or less in terms of wave number in one hole (a common absorption region in which chemical species belonging to the group consisting of alkynes absorb) bandpass filter 372c to pass the light, the one hole, in terms of wavenumber 2450cm ^-1 or 2550 cm ^-1 Bandpass filter 372d which transmits light in the wavelength band below (correction region) is fitted. Also, nothing is fitted into the remaining one of the five holes formed in the filter board 372.

The filter panel 372 is disposed at a position that intersects the optical path of the light emitted from the infrared irradiation device 330 between the gas introduction unit 320 (more strictly, the measurement target gas) and the lens 351.
When the motor 371 is driven to rotate, the filter board 372 rotates, (α) the bandpass filter 372a intersects the optical path, (β) the bandpass filter 372b intersects the optical path, and (γ) the bandpass filter 372c optical path. , (Δ) a state in which the band-pass filter 372d intersects the optical path, and (ε) a state in which a hole in the filter panel 372 to which nothing is fitted intersects the optical path.

(Alpha) in the state where the band-pass filter 372a intersects the optical path, of the light led to the outside from the gas accommodating section 320, only light bands in terms of wavenumber 2800 cm ^-1 or 3000 cm ^-1 or less in the wavelength band Passes the pass filter 372a.
(Beta) in the state where the band-pass filter 372b intersects the optical path, of the light led to the outside from the gas accommodating section 320, only light bands in terms of wavenumber 3000 cm ^-1 or 3200 cm ^-1 or less in the wavelength band Passes the pass filter 372b.
(Γ) In a state where the bandpass filter 372c intersects the optical path, only the light in the wavelength band of 3200 cm ⁻¹ or more and 3400 cm ⁻¹ or less in terms of wave number is banded out of the light guided to the outside from the gas introduction unit 320. Passes the pass filter 372c.
(Δ) In a state where the bandpass filter 372d intersects the optical path, only the light in the wavelength band of 2450 cm ⁻¹ or more and 2550 cm ⁻¹ or less in terms of wave number is banded out of the light guided to the outside from the gas introduction unit 320. Passes the pass filter 372d.
(Ε) In a state where the hole of the filter board 372 to which nothing is fitted intersects the optical path, the light guided to the outside from the gas introduction part 320 passes through the hole.
A filter fitted in a hole formed in the filter board 372 or light passing through the hole is detected by the photodiode 360 through the lens 351. In this way, the filter switching device 370 switches the wavelength band of light detected by the photodiode 360.

The filter control device 373 switches the filter (or hole) crossing the optical path by controlling the rotation and stop of the motor 371, and a programmable controller (a program storing a program for controlling the operation of the motor 371) Programmable Logic Controller (PLC).
The filter control device 373 is connected to the motor 371 and transmits a signal (control signal) for controlling the rotation speed of the motor 371 to the motor 371.
Further, the filter control device 373 has a filter No. which is a signal indicating a filter (or a hole) intersecting the optical path. Output a signal.
The filter switching frequency by the filter board 372 and the filter control device 373 is sufficiently lower than the optical chopping frequency by the above-described rotating board 342 and chopper control device 343 (desirably, the optical chopping frequency is several tenths). It is necessary to set.

The signal processing circuit 380 removes noise from the received light intensity signal acquired from the photodiode 360.
The signal processing circuit 380 is connected to the chopper device 340 and acquires (receives) a reference signal from the chopper device 340.
The signal processing circuit 380 is connected to the photodiode 360 and acquires (receives) a received light intensity signal from the photodiode 360.
Based on the reference signal and the received light intensity signal, the signal processing circuit 380 extracts “a component synchronized with a periodic intensity change” in the received light intensity signal, thereby removing a noise component included in the received light intensity signal.
The signal processing circuit 380 transmits the received light intensity signal from which the noise component has been removed to the analysis device 390. When the signal processing circuit 380 removes noise from the received light intensity signal, the resolution of the received light intensity signal is improved, and a minute change (or a minute hydrocarbon concentration) of the hydrocarbon concentration can be measured with higher accuracy. It is.

The analysis device 390 is an embodiment of the analysis unit according to the present invention. Based on the light detected by the photodiode 360, “a common absorption region absorbed by chemical species belonging to each group” for the measurement target gas. Is calculated, and the sum of the concentrations of the chemical species belonging to the groups respectively corresponding to these absorption regions is calculated.
The analysis device 390 mainly includes an analysis unit 391, an input unit 392, a display unit 393, and the like.

  The analysis unit 391 stores various programs and the like (for example, an absorbance calculation program and a concentration calculation program described later), expands these programs and the like, performs predetermined calculations according to these programs and the like, and outputs the calculation results and the like. Can be remembered.

The analysis unit 391 may actually have a configuration in which a CPU, a ROM, a RAM, an HDD, and the like are connected by a bus, or may be configured by a one-chip LSI or the like.
The analysis unit 391 of this embodiment is a dedicated product, but it can also be achieved by storing the above-described program in a commercially available personal computer or workstation.

The analysis unit 391 is connected to the filter switching device 370 (more precisely, the filter control device 373). It is possible to acquire (receive) a signal.
The analysis unit 391 is connected to the signal processing circuit 380, and can acquire (receive) a received light intensity signal (more precisely, a noise component is removed).

  The configuration of the input unit 392 and the display unit 393 is substantially the same as that of the input unit 192 and the display unit 193 shown in FIG.

Below, the detailed structure of the analysis part 391 is demonstrated.
The analysis unit 391 functionally includes a storage unit 391a, an absorbance calculation unit 391b, a concentration calculation unit 391c, and the like.

  The storage unit 391a stores information used for various calculations performed in the analysis unit 391, calculation results, and the like.

The storage unit 391a stores a spectrum of the reference gas.
The method for acquiring the reference gas spectrum is substantially the same as the hydrocarbon concentration measuring apparatus 100 shown in FIG.

The absorbance calculation unit 391b calculates the absorbance of the common absorption region of the measurement target gas based on the light detected by the photodiode 360.
Substantially, the analysis unit 391 performs a predetermined calculation or the like according to the absorbance calculation program, thereby functioning as the absorbance calculation unit 391b.

The absorbance calculation unit 391b receives the filter No. from the filter switching device 370. A signal is acquired and a received light intensity signal is acquired from the signal processing circuit 380.
The filter No. acquired from the filter switching device 370 The signal is substantially information representing the wavelength band of light received by the photodiode 360.
Therefore, the absorbance calculation unit 391b has a filter No. By collating the signal with the received light intensity signal, it is possible to specify the wavelength (wavelength band) corresponding to the acquired received light intensity signal.

  The absorbance calculation unit 391b is configured to absorb the chemical species belonging to the group consisting of “alkane and alkene” of the measurement target gas based on “the received light intensity signal in which the wavelength (wavelength band) is specified” and “the spectrum of the reference gas”. Absorbance in the absorption region ”,“ Absorbance in the common absorption region absorbed by chemical species belonging to the group consisting of aromatic hydrocarbons ”and“ Absorbance in the common absorption region absorbed by chemical species belonging to the group consisting of alkynes ” Calculate each.

More specifically, the absorbance calculation section 391b is of the "wavelength light reception intensity signal (wavelength band) is identified," received light intensity signal corresponding to, in terms of wavenumber 2800 cm ^-1 or 3000 cm ^-1 or less in the wavelength band To calculate the “light receiving intensity of a common absorption region absorbed by chemical species belonging to the group consisting of alkanes and alkenes”.
Further, the absorbance calculation section 391b is of the "wavelength light reception intensity signal (wavelength band) is identified,""aromatic light-intensity-signal corresponding to the wavelength range 3000 cm ^-1 or 3200 cm ^-1 following in terms of wavenumber The light receiving intensity of a common absorption region absorbed by chemical species belonging to the hydrocarbon group is calculated.
Further, the absorbance calculation unit 391b converts the received light intensity signal corresponding to the wavelength band of 3200 cm ⁻¹ or more and 3400 cm ⁻¹ or less in terms of “wavelength (wavelength band) of the received light intensity signal with specified wavelength (wavelength band)” from “alkyne”. The light receiving intensity of a common absorption region absorbed by chemical species belonging to a certain group ”is calculated.

Next, the absorbance calculation unit 391b calculates the calculated “light-receiving intensity of a common absorption region absorbed by chemical species belonging to the group consisting of alkanes and alkenes” and “the group consisting of alkanes and alkenes in the spectrum of the reference gas”. Based on the intensity of light in the wavelength band corresponding to the common absorption region absorbed by the chemical species to which it belongs, "absorbance of the common absorption region absorbed by the chemical species belonging to the group consisting of alkane and alkene" for the measurement target gas Is calculated.
Similarly, the absorbance calculation unit 391b performs “absorbance of a common absorption region absorbed by chemical species belonging to the group consisting of aromatic hydrocarbons” and “chemical species belonging to the group consisting of alkynes” for the measurement target gas. The absorbance of the common absorption region ”is calculated.

  “Absorbance of a common absorption region absorbed by chemical species belonging to the group consisting of alkanes and alkenes”, “Absorbance of common absorption region absorbed by chemical species belonging to the group consisting of aromatic hydrocarbons” for the measurement target gas, The calculation of “absorbance of a common absorption region absorbed by a chemical species belonging to the group consisting of alkynes” is performed using Equation 1 above.

The concentration calculation unit 391c determines whether the chemical species belonging to the group consisting of alkane and alkene is based on the “absorbance of the common absorption region absorbed by the chemical species belonging to the group consisting of alkane and alkene” calculated by the absorbance calculation unit 391b. "Sum of concentrations" is calculated, and "Sum of concentrations of chemical species belonging to group consisting of aromatic hydrocarbons" is calculated based on "absorbance of common absorption region absorbed by chemical species belonging to groups consisting of aromatic hydrocarbons" And “the sum of the concentrations of chemical species belonging to the group consisting of alkynes” is calculated based on “absorbance of the common absorption region absorbed by chemical species belonging to the group consisting of alkynes”.
Substantially, the analysis unit 391 functions as the concentration calculation unit 391c by performing a predetermined calculation or the like according to the concentration calculation program.
The configuration of the concentration calculation unit 391c is substantially the same as that of the concentration calculation unit 191c shown in FIG.

As described above, the hydrocarbon concentration measuring apparatus 300 is
Light in a wavelength band that includes a common absorption region that is absorbed by one or more chemical species in the gas to be measured (a gas containing hydrocarbons of one or more chemical species) (in this example, converted to wave number) an infrared radiator 330 which irradiates the 2000 cm ^-1 or 4000 cm ^-1 the following waveband light) Te,
A photodiode 360 that detects light irradiated to the measurement target gas by the infrared irradiation device 330;
The absorbance of the common absorption region of the measurement target gas is calculated based on the light detected by the photodiode 360, and the wavelength of the common absorption region among one or more chemical species included in the measurement target gas is calculated based on the absorbance. An analysis device 390 that calculates the sum of the concentrations of chemical species that absorb light in the band (that is, chemical species belonging to a group corresponding to a common absorption region);
It comprises.
By configuring in this way, there is no delay in response to changes in the concentration and composition of the gas to be measured, and it is possible to measure hydrocarbon concentration in real time, ensuring measurement responsiveness. It is.
In addition, when the concentration or composition of the gas to be measured changes, the sum of the concentrations of chemical species that absorb light in the common absorption region (that is, chemical species belonging to the group corresponding to the common absorption region) is accurately calculated. Is possible.

In this embodiment, the filter switching device 370 switches the wavelength band of light detected by the single photodiode 360. However, the present invention is not limited to this, and the wavelength bands ( It is also possible to omit the filter switching device 370 by providing a band-pass filter that transmits only the absorption region.
In such a configuration, it is possible to simultaneously measure a plurality of absorption regions, and the responsiveness of the hydrocarbon concentration measurement is improved.
In addition, a plurality of photodiodes capable of detecting different wavelength bands are prepared, and the bandpass filter is provided by making the detectable wavelength bands of these photodiodes correspond to different “common absorption regions”. It can be omitted.

  Hereinafter, a hydrocarbon concentration measuring apparatus 400 which is a fourth embodiment of the hydrocarbon concentration measuring apparatus according to the present invention will be described with reference to FIG.

The hydrocarbon concentration measuring device 400 measures the concentration of hydrocarbons contained in the measurement target gas.
As shown in FIG. 8, the hydrocarbon concentration measuring apparatus 400 mainly includes an optical rail 410, a gas introduction container 421 including a gas introduction container 421, an irradiation side window 422, and a detection side window 423, an infrared irradiation apparatus 430, a lens 451, a diffraction grating. 452, a line sensor 460, a sensor control device 470, a signal processing circuit 480, an analysis device 490, and the like.

Among the members constituting the hydrocarbon concentration measuring apparatus 400, the optical rail 410, the gas introducing section 420, the lens 451, the diffraction grating 452, the sensor control apparatus 470, and the signal processing circuit 480 are respectively shown in FIG. Since the optical rail 110, the gas introduction unit 120, the lens 151, the diffraction grating 152, the sensor control unit 170, and the signal processing circuit 180 in the apparatus 100 have substantially the same configuration, detailed description thereof is omitted.
The analysis device 490 includes an analysis unit 491, an input unit 492, and a display unit 493. The analysis unit 491 functionally includes a storage unit 491a, an absorbance calculation unit 491b, a concentration calculation unit 491c, and the like. 1 is substantially the same as the analyzing apparatus 190 shown in FIG.

The infrared irradiation device 430 is an embodiment of the irradiation unit according to the present invention. In the measurement target gas introduced into the internal space 421a of the gas introduction container 421, (a) a chemical species belonging to the group consisting of alkane and alkene is present. A common absorption region to absorb, (b) a common absorption region to be absorbed by a chemical species belonging to the group consisting of aromatic hydrocarbons, and (c) a common absorption region to be absorbed by a chemical species belonging to the group consisting of alkynes. Irradiates light of a wavelength band including.
The infrared irradiation device 430 includes a BB-MIR-LED (Broad Band Mid-IR Light Emission Diode) 431 and an LED control device 432.

BB-MIR-LED (Broad Band Mid-IR Light Emission Diode) 431 is capable of generating infrared radiation including a wavelength band of 2800 cm ^-1 or 3400 cm ^-1 or less in terms of wavenumber, and the infrared ray irradiation This is a semiconductor device capable of changing the intensity (intensity of light).

The LED control device 432 is a device that controls the intensity of light emitted from the BB-MIR-LED 431.
The LED control device 432 is connected to the BB-MIR-LED 431 and transmits an LED control signal that is a signal for controlling the intensity (light quantity) of light emitted from the BB-MIR-LED 431. Based on the LED control signal, the intensity of light emitted from the BB-MIR-LED 431 is modulated at a predetermined period (the intensity of the light changes so that the intensity appears alternately).
The LED control device 432 is connected to the signal processing circuit 480 and transmits a signal indicating the modulation frequency (reciprocal of the modulation period) of the intensity of light emitted from the BB-MIR-LED 431 to the signal processing circuit 480 as a reference signal.

  The light (infrared rays) emitted from the BB-MIR-LED 431 passes through the irradiation side window 422 of the gas introduction unit 420, is guided to the internal space 421a of the gas introduction container 421, and is applied to the measurement target gas introduced into the internal space 421a. Irradiated. Then, the light irradiated to the measurement target gas passes through the detection side window 423 of the gas introduction unit 420 and is guided to the outside of the gas introduction unit 420.

As described above, the hydrocarbon concentration measuring apparatus 400 is
Light in a wavelength band that includes a common absorption region that is absorbed by one or more chemical species in the gas to be measured (a gas containing hydrocarbons of one or more chemical species) (in this example, converted to wave number) the infrared radiator 430 which irradiates the 2000 cm ^-1 or 4000 cm ^-1 the following waveband light) Te,
A line sensor 460 that detects light irradiated to the measurement target gas by the infrared irradiation device 430;
The absorbance of the common absorption region of the measurement target gas is calculated based on the light detected by the line sensor 460, and the wavelength of the common absorption region among one or more chemical species included in the measurement target gas based on the absorbance. An analysis device 490 that calculates the sum of the concentrations of chemical species that absorb light in the band (ie, chemical species belonging to a group corresponding to a common absorption region);
It comprises.
By configuring in this way, there is no delay in response to changes in the concentration and composition of the gas to be measured, and it is possible to measure hydrocarbon concentration in real time, ensuring measurement responsiveness. It is.
In addition, when the concentration or composition of the gas to be measured changes, the sum of the concentrations of chemical species that absorb light in the common absorption region (that is, chemical species belonging to the group corresponding to the common absorption region) is accurately calculated. Is possible.

The infrared irradiation device 430 of the hydrocarbon concentration measuring device 400 is
A BB-MIR-LED 431 capable of changing the intensity of light to be irradiated;
An LED control device 432 that controls the intensity of light emitted by the BB-MIR-LED 431;
It comprises.
With this configuration, the modulation frequency of light intensity is increased (approximately several GHz) compared to the modulation frequency (approximately 1 kHz) in the case of performing mechanical light modulation such as the chopper device 140 illustrated in FIG. This contributes to improving the accuracy of hydrocarbon measurement.
Further, since the BB-MIR-LED 431 and the LED control device 432 do not have mechanical drive parts such as the motor 141 of the chopper device 140 shown in FIG. 1, the reliability (stability and maintainability) of the device is improved. .

  Hereinafter, a hydrocarbon concentration measuring apparatus 500 which is a fifth embodiment of the hydrocarbon concentration measuring apparatus according to the present invention will be described with reference to FIG.

The hydrocarbon concentration measuring apparatus 500 measures the concentration of hydrocarbons contained in the measurement target gas.
As shown in FIG. 9, the hydrocarbon concentration measuring apparatus 500 mainly includes an optical rail 510, a gas introduction container 521, an irradiation side window 522, and a detection side window 523, a gas introduction section 520, a BB-MIR-LED 531, and an LED control apparatus 532. And the like, an infrared irradiation device 530, a lens 551, a diffraction grating 552, photodiodes 560, 560..., A signal switching device 570, a signal processing circuit 580, an analysis device 590, and the like.

Among the members constituting the hydrocarbon concentration measuring apparatus 500, the optical rail 510, the gas introducing part 520, the lens 551, and the diffraction grating 552 are respectively the optical rail 110 and the gas introducing part in the hydrocarbon concentration measuring apparatus 100 shown in FIG. Since the configuration is substantially the same as that of the lens 120, the lens 151, and the diffraction grating 152, a detailed description thereof will be omitted.
Among the members constituting the hydrocarbon concentration measuring device 500, the photodiodes 560, 560..., The signal switching device 570, and the signal processing circuit 580 are respectively the photodiode 260. 260, the signal switching device 270 and the signal processing circuit 280 have substantially the same configuration, and thus detailed description thereof is omitted.
The analysis device 590 includes an analysis unit 591, an input unit 592, and a display unit 593. The analysis unit 591 functionally includes a storage unit 591a, an absorbance calculation unit 591b, a concentration calculation unit 591c, and the like. Since the configuration is substantially the same as the analysis device 290 shown in FIG.
Of the members constituting the hydrocarbon concentration measuring apparatus 500, the infrared irradiation apparatus 530 has substantially the same configuration as the infrared irradiation apparatus 430 in the hydrocarbon concentration measuring apparatus 400 shown in FIG.

As described above, the hydrocarbon concentration measuring apparatus 500 is
Light in a wavelength band that includes a common absorption region that is absorbed by one or more chemical species in the gas to be measured (a gas containing hydrocarbons of one or more chemical species) (in this example, converted to wave number) the infrared radiator 530 which irradiates the 2000 cm ^-1 or 4000 cm ^-1 the following waveband light) Te,
Photodiodes 560, 560,... For detecting the light irradiated to the measurement target gas by the infrared irradiation device 530;
Based on the light detected by the photodiodes 560, 560..., The absorbance of the common absorption region of the measurement target gas is calculated, and based on the absorbance, common among one or more chemical species included in the measurement target gas An analyzer 590 that calculates the sum of the concentrations of chemical species that absorb light in the wavelength band of the absorption region (that is, chemical species that belong to a group corresponding to a common absorption region);
It comprises.
By configuring in this way, there is no delay in response to changes in the concentration and composition of the gas to be measured, and it is possible to measure hydrocarbon concentration in real time, ensuring measurement responsiveness. It is.
In addition, when the concentration or composition of the gas to be measured changes, the sum of the concentrations of chemical species that absorb light in the common absorption region (that is, chemical species belonging to the group corresponding to the common absorption region) is accurately calculated. Is possible.

The infrared irradiation device 530 of the hydrocarbon concentration measuring device 500 is
BB-MIR-LED 531 capable of changing the intensity of light to be irradiated;
An LED controller 532 that controls the intensity of light emitted by the BB-MIR-LED 531;
It comprises.
By configuring in this way, the modulation frequency of the light intensity is increased (about several GHz) compared to the modulation frequency (about 1 kHz) in the case of performing mechanical light modulation as in the chopper device 240 shown in FIG. This contributes to improving the accuracy of hydrocarbon measurement.
Further, since the BB-MIR-LED 531 and the LED control device 532 do not have mechanical drive parts such as the motor 241 of the chopper device 240 shown in FIG. 6, the reliability (stability and maintainability) of the device is improved. .

  Hereinafter, a hydrocarbon concentration measuring apparatus 600 that is a sixth embodiment of the hydrocarbon concentration measuring apparatus according to the present invention will be described with reference to FIG.

The hydrocarbon concentration measuring apparatus 600 measures the concentration of hydrocarbons contained in the measurement target gas.
As shown in FIG. 10, the hydrocarbon concentration measuring apparatus 600 mainly includes an optical rail 610, a gas introduction container 621, an irradiation side window 622, and a detection side window 623, a BB-MIR-LED 631, and an LED control apparatus 632. An infrared irradiation device 630 including a lens 651, a photodiode 660, a filter switching device 670 including a motor 671, a filter board 672, and a filter control device 673, a signal processing circuit 680, an analysis device 690, and the like.

Among the members constituting the hydrocarbon concentration measuring apparatus 600, the optical rail 610, the gas introducing section 620, the lens 651, and the diffraction grating 652 are the optical rail 110 and the gas introducing section in the hydrocarbon concentration measuring apparatus 100 shown in FIG. Since the configuration is substantially the same as that of the lens 120, the lens 151, and the diffraction grating 152, a detailed description thereof will be omitted.
Among the members constituting the hydrocarbon concentration measuring device 600, the photodiode 660, the filter switching device 670, and the signal processing circuit 680 are the photodiode 360, the filter switching device 370, and the like in the hydrocarbon concentration measuring device 300 shown in FIG. Since the configuration is substantially the same as that of the signal processing circuit 380, detailed description thereof is omitted.
The analysis device 690 includes an analysis unit 691, an input unit 692, and a display unit 693. The analysis unit 691 functionally includes a storage unit 691a, an absorbance calculation unit 691b, a concentration calculation unit 691c, and the like. Since the configuration is substantially the same as the analysis device 390 shown in FIG.
Of the members constituting the hydrocarbon concentration measuring apparatus 600, the infrared irradiation apparatus 630 has substantially the same configuration as the infrared irradiation apparatus 430 in the hydrocarbon concentration measuring apparatus 400 shown in FIG.

As described above, the hydrocarbon concentration measuring apparatus 600 is
Light in a wavelength band that includes a common absorption region that is absorbed by one or more chemical species in the gas to be measured (a gas containing hydrocarbons of one or more chemical species) (in this example, converted to wave number) the infrared radiator 630 which irradiates the 2000 cm ^-1 or 4000 cm ^-1 the following waveband light) Te,
A photodiode 660 for detecting light irradiated to the measurement target gas by the infrared irradiation device 630;
Based on the light detected by the photodiode 660, the absorbance of the common absorption region of the measurement target gas is calculated, and the wavelength of the common absorption region among one or more chemical species included in the measurement target gas based on the absorbance. An analysis device 690 that calculates the sum of the concentrations of chemical species that absorb light in the band (ie, chemical species that belong to a group corresponding to a common absorption region);
It comprises.
By configuring in this way, there is no delay in response to changes in the concentration and composition of the gas to be measured, and it is possible to measure hydrocarbon concentration in real time, ensuring measurement responsiveness. It is.
In addition, when the concentration or composition of the gas to be measured changes, the sum of the concentrations of chemical species that absorb light in the common absorption region (that is, chemical species belonging to the group corresponding to the common absorption region) is accurately calculated. Is possible.

The infrared irradiation device 630 of the hydrocarbon concentration measuring device 600 is
A BB-MIR-LED 631 capable of changing the intensity of light to be irradiated;
An LED control device 632 for controlling the intensity of light emitted by the BB-MIR-LED 531;
It comprises.
With this configuration, the modulation frequency of the light intensity is increased (approximately several GHz) compared to the modulation frequency (approximately 1 kHz) in the case of performing mechanical light modulation such as the chopper device 340 shown in FIG. This contributes to improving the accuracy of hydrocarbon measurement.
Further, since the BB-MIR-LED 631 and the LED control device 632 do not have mechanical drive parts such as the motor 341 of the chopper device 340 shown in FIG. 7, the reliability (stability and maintenance performance) of the device is improved. .

  Hereinafter, a hydrocarbon concentration measuring apparatus 700 as a seventh embodiment of the hydrocarbon concentration measuring apparatus according to the present invention will be described with reference to FIG.

The hydrocarbon concentration measuring device 700 measures the concentration of hydrocarbons contained in the measurement target gas.
As shown in FIG. 11, the hydrocarbon concentration measuring apparatus 700 mainly includes an optical rail 710, a gas introducing section 720 including a gas introducing container 721, an irradiation side window 722, and a detection side window 723, an infrared irradiation apparatus 730, a lens 751, and a photodiode. 760, a correction photodiode 765, a signal processing circuit 780, a correction signal processing circuit 785, an analysis device 790, and the like.

  Among the members constituting the hydrocarbon concentration measuring apparatus 700, the optical rail 710, the gas introducing part 720, and the lens 751 are respectively the optical rail 110, the gas introducing part 120, and the lens 151 in the hydrocarbon concentration measuring apparatus 100 shown in FIG. Since the configuration is substantially the same, detailed description is omitted.

  The infrared irradiation device 730 is an embodiment of the irradiation unit according to the present invention. In the measurement target gas introduced into the internal space 721a of the gas introduction container 721, (a) a chemical species belonging to the group consisting of alkane and alkene is present. A common absorption region to be absorbed, (b) a common absorption region to be absorbed by a chemical species belonging to the group consisting of aromatic hydrocarbons, and (c) a common absorption region to be absorbed by a chemical species belonging to the group consisting of alkynes. It irradiates light in any one of the wavelength bands.

  The infrared irradiation device 730 mainly includes a first light emitting diode 731a, a second light emitting diode 731b, a third light emitting diode 731c, a first duplexer 732a, a second duplexer 732b, a third duplexer 732c, and a first multiplexer. 733a, a second multiplexer 733b, a lens 734, a first light emitting diode controller 735a, a second light emitting diode controller 735b, a third light emitting diode controller 735c, a light emitting diode selector 736, and the like.

The first LED 731a is 2800 cm ^-1 or 3000 cm ^-1 or less in the wavelength range, in terms of wavenumber, i.e. (a) in the wavelength band where the chemical species belonging to the group consisting of alkanes and alkenes corresponds to the common absorption region where Infrared (light) is generated.
The first light-emitting diode 731a of the present embodiment is formed of an NB-MIR-LED which generates light of 2800 cm ^-1 or 3000 cm ^-1 or less in the wavelength range, in terms of wavenumber (Narrow Band Mid-IR Light Emission Diode).
The intensity of light generated by the first light emitting diode 731a can be changed by changing the voltage applied to the first light emitting diode 731a.

Second LED 731b is a waveband corresponding to the common absorption region 3000 cm ^-1 or 3200 cm ^-1 or less in the wavelength range, in terms of wavenumber, namely that (b) the chemical species belonging to the group consisting of aromatic hydrocarbons absorb Of infrared rays (light).
Second LED 731b of this embodiment formed of an NB-MIR-LED which generates light of 3000 cm ^-1 or 3200 cm ^-1 or less in the wavelength range, in terms of wavenumber.
The intensity of light generated by the second light emitting diode 731b can be changed by changing the voltage applied to the second light emitting diode 731b.

The third light emitting diode 731c has a wavelength band of 3200 cm ⁻¹ or more and 3400 cm ⁻¹ or less in terms of wave number, that is, (c) an infrared ray having a wavelength band corresponding to a common absorption region absorbed by a chemical species belonging to the group consisting of alkynes ( Light).
The third light emitting diode 731c of this embodiment is composed of an NB-MIR-LED that generates light in a wavelength band of 3200 cm ⁻¹ or more and 3400 cm ⁻¹ or less in terms of wave number.
The intensity of light generated by the third light emitting diode 731c can be changed by changing the voltage applied to the third light emitting diode 731c.

The first demultiplexer 732a, the second demultiplexer 732b, and the third demultiplexer 732c are optical devices that divide one input light beam into two light beams and output them.
The input side port of the first duplexer 732a is connected to the first light emitting diode 731a by an optical fiber. The light emitted from the first light emitting diode 731a is input to the first demultiplexer 732a through the optical fiber, divided into two light beams, and output from the two output ports.
The input side port of the second duplexer 732b is connected to the second light emitting diode 731b by an optical fiber. The light emitted from the second light emitting diode 731b passes through the optical fiber, is input to the second duplexer 732b, is divided into two light beams, and is output from the two output ports.
The input side port of the third duplexer 732c is connected to the third light emitting diode 731c by an optical fiber. The light emitted from the third light emitting diode 731c is input to the third demultiplexer 732c through the optical fiber, divided into two light beams, and output from the two output ports.
Specific examples of the first demultiplexer 732a, the second demultiplexer 732b, and the third demultiplexer 732c include various beam splitters (prism type, planar type (half mirror, etc.), wedge substrate type, etc.). .

The first multiplexer 733a and the second multiplexer 733b are optical devices that synthesize three input light beams and output them as one light beam.
The three input ports of the first multiplexer 733a are respectively connected to one output port of the first duplexer 732a, one output port of the second duplexer 732b, and the third duplexer 732c by optical fibers. Connected to one of the output ports. Light output from one output side port of the first demultiplexer 732a, one output side port of the second demultiplexer 732b, and one output side port of the third demultiplexer 732c is a corresponding optical fiber. Are input to the first multiplexer 733a, combined and output as one light beam.
The three input ports of the second multiplexer 733b are respectively connected to the other output port of the first duplexer 732a, the other output port of the second duplexer 732b, and the third duplexer 732c by optical fibers. To the other output side port. The light output from the other output side port of the second demultiplexer 732b, the other output side port of the second demultiplexer 732b, and the other output side port of the third demultiplexer 732c is a corresponding optical fiber. Are input to the second multiplexer 733b, combined, and output as one light beam.
Specific examples of the first multiplexer 733a and the second multiplexer 733b include various beam splitters (prism type, planar type (half mirror, etc.), wedge substrate type, etc.).

  As will be described in detail later, in this embodiment, light is not simultaneously input to two or more input ports for any of the first multiplexer 733a and the second multiplexer 733b. Therefore, the first multiplexer 733a and the second multiplexer 733b substantially output light input from any one of the three input ports from the output port.

The lens 734 is a lens fixed to the optical rail 710. The lens 734 is disposed at a position facing the irradiation side window 722 of the gas introduction unit 720.
The lens 734 is connected to the output side port of the first multiplexer 733a by an optical fiber.
The light output from the output side port of the first multiplexer 733a reaches the lens 734 through the optical fiber, converges at the lens 734, passes through the irradiation side window 722, and passes through the internal space of the gas introduction unit 720. The measurement target gas introduced into 721a is irradiated.

The first light emitting diode control device 735a is a device that controls the intensity of light emitted from the first light emitting diode 731a.
The first light emitting diode control device 735a is connected to the first light emitting diode 731a, and an LED control signal (substantially, the first light emitting) is a signal for controlling the intensity (light quantity) of the light emitted by the first light emitting diode 731a. A signal indicating the magnitude of the voltage applied to the diode 731a is transmitted. Based on the LED control signal, the intensity of the light emitted from the first light emitting diode 731a is modulated at a predetermined period (the intensity changes so that the intensity appears alternately).

The second light emitting diode control device 735b is a device that controls the intensity of light emitted by the second light emitting diode 731b.
The second light emitting diode control device 735b is connected to the second light emitting diode 731b, and an LED control signal (substantially, the second light emitting) is a signal for controlling the intensity (light quantity) of light emitted from the second light emitting diode 731b. A signal indicating the magnitude of the voltage applied to the diode 731b is transmitted. Based on the LED control signal, the intensity of the light emitted from the second light emitting diode 731b is modulated at a predetermined period (the intensity changes so that the intensity appears alternately).

The third light emitting diode control device 735c is a device that controls the intensity of light emitted from the third light emitting diode 731c.
The third light emitting diode control device 735c is connected to the third light emitting diode 731c, and an LED control signal (substantially, the third light emitting) is a signal for controlling the intensity (light quantity) of light emitted from the third light emitting diode 731c. A signal indicating the magnitude of the voltage applied to the diode 731c is transmitted. Based on the LED control signal, the intensity of the light emitted from the third light emitting diode 731c is modulated at a predetermined period (the intensity changes so that the intensity appears alternately).

The light-emitting diode selection device 736 operates as to which of the first light-emitting diode control device 735a, the second light-emitting diode control device 735b, and the third light-emitting diode control device 735c operates, and thus the first light-emitting diode 731a and the second light-emitting diode 731b. This is a device for selecting which of the third light emitting diodes 731c emits light.
The light emitting diode selection device 736 of this embodiment stores a program for selecting which one of the first light emitting diode control device 735a, the second light emitting diode control device 735b, and the third light emitting diode control device 735c operates. It consists of a programmable controller.

The light emitting diode selection device 736 is connected to the first light emitting diode control device 735a, the second light emitting diode control device 735b, and the third light emitting diode control device 735c, and is a signal for operating any one of them. Send an operation signal. Of the first light emitting diode control device 735a, the second light emitting diode control device 735b, and the third light emitting diode control device 735c, the one that has acquired the operation signal operates only while the operation signal is being acquired (correspondingly LED signal is sent to the light emitting diode).
The light emitting diode selection device 736 is connected to the analysis device 790 (more precisely, the analysis unit 791), and operates among the first light emitting diode control device 735a, the second light emitting diode control device 735b, and the third light emitting diode control device 735c. LED No. which is a signal indicating the light emitting device (and thus the light emitting diode control device 735a, the second light emitting diode control device 735b, and the third light emitting diode control device 735c). The signal is transmitted to the analysis device 790.
The light emitting diode selection device 736 is connected to the signal processing circuit 780 and the correction signal processing circuit 785, and any one of the first light emitting diode control device 735a, the second light emitting diode control device 735b, and the third light emitting diode control device 735c is used. A reference signal, which is a signal indicating the phase of modulation of the intensity of emitted light, is transmitted to the signal processing circuit 780 and the correction signal processing circuit 785.

  As described above, the infrared irradiation device 730 is configured such that (a) the chemical species belonging to the group consisting of alkane and alkene is absorbed into the measurement target gas introduced into the internal space 721a of the gas introduction container 721, (b Light in any of the wavelength bands of: (a) a common absorption region absorbed by a chemical species belonging to the group consisting of aromatic hydrocarbons, and (c) a common absorption region absorbed by a chemical species belonging to the group consisting of alkynes It is possible to select and irradiate.

The photodiode 760 is an embodiment of the detection unit according to the present invention, and detects light irradiated to the measurement target gas by the infrared irradiation device 730.
The photodiode 760 is a semiconductor element that generates an electrical signal (light reception intensity signal) corresponding to the intensity of received light.

The signal processing circuit 780 removes noise from the received light intensity signal acquired from the photodiode 760.
The signal processing circuit 780 is connected to the light emitting diode selection device 736 and acquires (receives) a reference signal from the light emitting diode selection device 736.
The signal processing circuit 780 is connected to the photodiode 760 and acquires (receives) a received light intensity signal from the photodiode 760.
Based on the reference signal and the received light intensity signal, the signal processing circuit 780 extracts “a component synchronized with a periodic intensity change” in the received light intensity signal, thereby removing a noise component included in the received light intensity signal.
The signal processing circuit 780 transmits the received light intensity signal from which the noise component has been removed to the analysis device 790. The signal processing circuit 780 removes noise from the received light intensity signal, so that the resolution of the received light intensity signal is improved, and a minute change (or a minute hydrocarbon concentration) of the hydrocarbon concentration can be measured with higher accuracy. It is.

The correction photodiode 765 detects light generated by the infrared irradiation device 730. The correction photodiode 765 is a semiconductor element that generates an electric signal (correction light reception intensity signal) corresponding to the intensity of received light, and is connected to the output side port of the second multiplexer 733b by an optical fiber.
Of the light generated by the infrared irradiation device 730, one of the light beams divided into two by one of the first demultiplexer 732a, the second demultiplexer 732b, and the third demultiplexer 732c is irradiated to the measurement target gas. Then, the other of the light beams divided into two is detected by the correction photodiode 765. Therefore, the light detected by the correction photodiode 765 is generated at the same timing in the same light source as the light irradiated to the measurement target gas.

The correction signal processing circuit 785 is for removing noise from the correction light-receiving intensity signal acquired from the correction photodiode 765.
The correction signal processing circuit 785 is connected to the light emitting diode selection device 736 and acquires (receives) a reference signal from the light emitting diode selection device 736.
The correction signal processing circuit 785 is connected to the correction photodiode 765 and acquires (receives) a correction light reception intensity signal from the correction photodiode 765.
The correction signal processing circuit 785 extracts “a component synchronized with a periodic intensity change” in the correction light reception intensity signal based on the reference signal and the correction light reception intensity signal, and is included in the correction light reception intensity signal. Remove noise components.
The correction signal processing circuit 785 transmits the correction light reception intensity signal from which the noise component has been removed to the analysis device 790. When the correction signal processing circuit 785 removes noise from the correction light reception intensity signal, the resolution of the correction light reception intensity signal is improved, and the accuracy of absorbance correction described later is improved.

The analysis device 790 is an embodiment of the analysis unit according to the present invention. Based on the light detected by the photodiode 760, the “common absorption region absorbed by the chemical species belonging to each group” for the measurement target gas. Is calculated, and the sum of the concentrations of the chemical species belonging to the groups respectively corresponding to these absorption regions is calculated.
The analysis device 790 mainly includes an analysis unit 791, an input unit 792, a display unit 793, and the like.

  The analysis unit 791 stores various programs and the like (for example, an absorbance calculation program and a concentration calculation program described later), expands these programs and the like, performs predetermined calculations according to these programs and the like, and outputs the calculation results and the like. Can be remembered.

The analysis unit 791 may actually have a configuration in which a CPU, a ROM, a RAM, an HDD, and the like are connected by a bus, or a configuration that includes a one-chip LSI or the like.
The analysis unit 791 of the present embodiment is a dedicated product, but it can also be achieved by storing the above-described program in a commercially available personal computer or workstation.

The analysis unit 791 is connected to the light emitting diode selection device 736, and the LED No. It is possible to acquire (receive) a signal.
The analysis unit 791 is connected to the signal processing circuit 780 and can acquire (receive) a received light intensity signal (more precisely, a noise component is removed) from the signal processing circuit 780.
The analysis unit 791 is connected to the correction signal processing circuit 785 and can acquire (receive) the received light intensity signal (more precisely, the noise component is removed) from the correction signal processing circuit 785.

The input unit 792 is connected to the analysis unit 791 and inputs various information / instructions related to the analysis by the hydrocarbon concentration measuring apparatus 700 to the analysis unit 791.
Although the input unit 792 of this embodiment is a dedicated product, the same effect can be achieved by using a commercially available keyboard, mouse, pointing device, button, switch, or the like.

The display unit 793 displays the input content from the input unit 792 to the analysis unit 791, the analysis result (measurement result of hydrocarbon concentration) by the analysis unit 791, and the like.
Although the display portion 793 of this embodiment is a dedicated product, the same effect can be achieved even if a commercially available monitor, liquid crystal display, or the like is used.

Below, the detailed structure of the analysis part 791 is demonstrated.
The analysis unit 791 functionally includes a storage unit 791a, an absorbance calculation unit 791b, a concentration calculation unit 791c, and the like.

  The storage unit 791a stores information used for various calculations performed in the analysis unit 791, calculation results, and the like.

The storage unit 791a stores the spectrum of the reference gas.
The method for acquiring the reference gas spectrum is substantially the same as the hydrocarbon concentration measuring apparatus 100 shown in FIG.

The absorbance calculation unit 191b calculates the absorbance of the common absorption region of the measurement target gas based on the light detected by the photodiode 760.
Substantially, the analysis unit 791 performs a predetermined calculation or the like according to the absorbance calculation program, thereby functioning as the absorbance calculation unit 791b.

The absorbance calculation unit 791b receives the LED No. from the light emitting diode selection device 736. A signal is acquired and a received light intensity signal is acquired from the signal processing circuit 780.
The LED No. acquired from the light emitting diode selection device 736 is obtained. The signal is a signal indicating whether the light received by the photodiode 760 is emitted from any one of the first light emitting diode 731a, the second light emitting diode 731b, and the third light emitting diode 731c. This is information representing the wavelength band of light received by the photodiode 760.
Therefore, the absorbance calculation unit 791b is LEDNo. By collating the signal with the received light intensity signal, it is possible to specify the wavelength (wavelength band) corresponding to the acquired received light intensity signal.

  The absorbance calculation unit 791b is configured to absorb the chemical species belonging to the group consisting of “alkane and alkene” of the measurement target gas based on “the received light intensity signal in which the wavelength (wavelength band) is specified” and “the spectrum of the reference gas”. Absorbance in the absorption region ”,“ Absorbance in the common absorption region absorbed by chemical species belonging to the group consisting of aromatic hydrocarbons ”and“ Absorbance in the common absorption region absorbed by chemical species belonging to the group consisting of alkynes ” Calculate each.

More specifically, the absorbance calculation unit 791b calculates “light reception intensity of a common absorption region absorbed by chemical species belonging to the group consisting of alkane and alkene” from the light reception intensity signal corresponding to the first light emitting diode 731a.
In addition, the absorbance calculation unit 791b calculates “the received light intensity of the common absorption region absorbed by the chemical species belonging to the group consisting of aromatic hydrocarbons” from the received light intensity signal corresponding to the second light emitting diode 731b.
In addition, the absorbance calculation unit 791b calculates “the received light intensity of the common absorption region absorbed by the chemical species belonging to the alkyne group” from the received light intensity signal corresponding to the third light emitting diode 731c.

Next, the absorbance calculation unit 791b calculates the “received light intensity of the common absorption region absorbed by the chemical species belonging to the group consisting of alkane and alkene” and “the group consisting of alkane and alkene in the spectrum of the reference gas”. Based on the intensity of light in the wavelength band corresponding to the common absorption region absorbed by the chemical species to which it belongs, "absorbance of the common absorption region absorbed by the chemical species belonging to the group consisting of alkane and alkene" for the measurement target gas Is calculated.
Similarly, the absorbance calculation unit 791b performs “absorbance of a common absorption region absorbed by chemical species belonging to the group consisting of aromatic hydrocarbons” and “chemical species belonging to the group consisting of alkynes” for the measurement target gas. The absorbance of the common absorption region ”is calculated.

  “Absorbance of a common absorption region absorbed by chemical species belonging to the group consisting of alkanes and alkenes”, “Absorbance of common absorption region absorbed by chemical species belonging to the group consisting of aromatic hydrocarbons” for the measurement target gas, The calculation of “absorbance of a common absorption region absorbed by a chemical species belonging to the group consisting of alkynes” is performed using Equation 1 above.

Further, the absorbance calculation unit 791b uses Equation 1 based on the “correction light reception signal” acquired from the correction signal processing circuit 785 and the “initial value of the correction light reception signal” stored in the storage unit 791a in advance. Calculated as "absorbance of a common absorption region absorbed by chemical species belonging to the group consisting of alkane and alkene", "absorbance of common absorption region absorbed by chemical species belonging to the group consisting of aromatic hydrocarbons" and " The “absorbance of the common absorption region absorbed by the chemical species belonging to the group consisting of alkyne” is corrected using the following formula 2.
Here, the “initial value of the light reception signal for correction” is, for example, immediately after maintenance such as replacement, cleaning, repair, etc. of the members constituting the infrared irradiation device 730, the correction photodiode 765, the correction signal processing circuit 785, etc. This is a value obtained by acquiring the correction light reception signal performed in step (b).

In Equation 2, (An) c indicates the absorbance after correction, and An indicates the absorbance before correction (absorbance calculated by Equation 1).
Further, (Ic) n indicates the received light intensity obtained from the corrected received light signal, and ((Ic) n) ₀ indicates the received light intensity obtained from the initial value of the corrected received light signal.

  By correcting the absorbance using Equation 2 above, it is possible to prevent a decrease in the accuracy of the hydrocarbon concentration measurement due to a change in the amount of light due to a cause such as deterioration of the members constituting the infrared irradiation device 730.

The concentration calculation unit 791c is configured to calculate the chemical species belonging to the group consisting of alkane and alkene based on the “absorbance of the common absorption region absorbed by the chemical species belonging to the group consisting of alkane and alkene” calculated by the absorbance calculation unit 791b. "Sum of concentrations" is calculated, and "Sum of concentrations of chemical species belonging to group consisting of aromatic hydrocarbons" is calculated based on "absorbance of common absorption region absorbed by chemical species belonging to groups consisting of aromatic hydrocarbons" And “the sum of the concentrations of chemical species belonging to the group consisting of alkynes” is calculated based on “absorbance of the common absorption region absorbed by chemical species belonging to the group consisting of alkynes”.
Substantially, the analysis unit 791 performs a predetermined calculation or the like according to the concentration calculation program, thereby functioning as the concentration calculation unit 791c.
The configuration of the concentration calculation unit 791c is substantially the same as that of the concentration calculation unit 191c shown in FIG.

As described above, the hydrocarbon concentration measuring apparatus 700 is
Light in a wavelength band that includes a common absorption region that is absorbed by one or more chemical species in the gas to be measured (a gas containing hydrocarbons of one or more chemical species) (in this example, converted to wave number) Te 2800 cm ^-1 or 3000 cm ^-1 the following waveband light, 3000 cm ^-1 or more, in terms of wavenumber 3200 cm ^-1 the following waveband light, in terms of wavenumber 3200 cm ^-1 or 3400 cm ^-1 or less in the wavelength band Infrared irradiation device 730 for irradiating any one of
A photodiode 760 for detecting light applied to the measurement target gas by the infrared irradiation device 730;
Based on the light detected by the photodiode 760, the absorbance of the common absorption region of the measurement target gas is calculated, and the wavelength of the common absorption region among the single or plural chemical species included in the measurement target gas is calculated based on the absorbance. An analysis device 790 that calculates a sum of concentrations of chemical species that absorb light in the band (that is, chemical species that belong to a group corresponding to a common absorption region);
It comprises.
By configuring in this way, there is no delay in response to changes in the concentration and composition of the gas to be measured, and it is possible to measure hydrocarbon concentration in real time, ensuring measurement responsiveness. It is.
In addition, when the concentration or composition of the gas to be measured changes, the sum of the concentrations of chemical species that absorb light in the common absorption region (that is, chemical species belonging to the group corresponding to the common absorption region) is accurately calculated. Is possible.

The hydrocarbon concentration measuring device 700 is
A correction photodiode 765 for detecting light generated by the infrared irradiation device 730;
The infrared irradiation device 730 of the hydrocarbon concentration measuring device 700 is:
A first light emitting diode 731a that emits light in a common absorption region absorbed by chemical species belonging to the group consisting of alkanes and alkenes;
A second light emitting diode 731b that emits light in a common absorption region that is absorbed by chemical species belonging to the group consisting of aromatic hydrocarbons;
A third light emitting diode 731c that emits light in a common absorption region that is absorbed by chemical species belonging to the group consisting of alkynes;
A first duplexer 732a that splits the light emitted by the first light emitting diode 731a into two;
A second duplexer 732b that splits the light emitted by the second light emitting diode 731b into two;
A third duplexer 732c that splits the light emitted by the third light emitting diode 731c into two parts;
One of the lights divided by the first demultiplexer 732a, one of the lights divided by the second demultiplexer 732b, and one of the lights divided by the third demultiplexer 732c are synthesized and used as the measurement target gas. A first multiplexer 733a for irradiating;
A correction photodiode that combines the other of the light divided by the first demultiplexer 732a, the other of the light divided by the second demultiplexer 732b, and the other of the light divided by the third demultiplexer 732c. A second multiplexer 733b that irradiates 765;
A first light emitting diode controller 735a for controlling the intensity of light emitted by the first light emitting diode 731a;
A second light emitting diode controller 735b for controlling the intensity of light emitted by the second light emitting diode 731b;
A third light emitting diode controller 735c for controlling the intensity of light emitted by the third light emitting diode 731c;
A light-emitting diode selector 736 that selects which of the three light-emitting diode controllers (first light-emitting diode controller 735a, second light-emitting diode controller 735b, and third light-emitting diode controller 735c) operates;
Comprising
The analysis device 790 of the hydrocarbon concentration measuring device 700 corrects the light intensity detected by the photodiode 760 based on the light intensity detected by the correction photodiode 765.
By configuring in this way, the infrared irradiation device 730 has all of the “function for selecting the wavelength band of the irradiated light”, “the function for modulating the intensity of the irradiated light”, and “the function for monitoring the light quantity of the light source”. It can be incorporated, and the apparatus can be made compact.

Below, one Embodiment of the hydrocarbon concentration measuring method which concerns on this invention is described using FIG.
One embodiment of the method for measuring hydrocarbon concentration according to the present invention is a method for measuring the concentration of hydrocarbons contained in the gas to be measured using the hydrocarbon concentration measuring apparatus 100. As shown in FIG. -It has detection process S1100 and analysis process S1200.

In the irradiation / detection step S1100, (a) a common absorption region absorbed by a chemical species belonging to the group consisting of alkane and alkene is absorbed into the measurement target gas, and (b) a common chemical species belonging to the group consisting of aromatic hydrocarbon is absorbed. And (c) a common absorption region that is absorbed by chemical species belonging to the group consisting of alkynes, and a step of detecting light irradiated to the measurement target gas.
In the irradiation / detection step S1100, the infrared irradiation device 130 has (a) a common absorption region in which a chemical species belonging to the group consisting of alkane and alkene is absorbed in the measurement target gas introduced into the internal space 121a of the gas introduction container 121, Irradiating light in a wavelength band including (b) a common absorption region absorbed by chemical species belonging to the group consisting of aromatic hydrocarbons, and (c) common absorption region absorbed by chemical species belonging to the group consisting of alkynes To do.
In the irradiation / detection step S1100, the line sensor 160 detects the light irradiated to the measurement target gas by the infrared irradiation device 130.
When the irradiation / detection step S1100 ends, the process proceeds to the analysis step S1200.

  The analysis step S1200 includes (a) a common absorption region that is absorbed by chemical species belonging to the group consisting of alkane and alkene based on the light detected in the irradiation / detection step S1100, and (b) a group consisting of aromatic hydrocarbons. Absorbance is calculated for each of the common absorption region absorbed by the chemical species to which it belongs, and (c) the common absorption region absorbed by the chemical species belonging to the group consisting of the alkyne, and (1) alkane and alkene based on the absorbance. The sum of the concentrations of the chemical species belonging to the group consisting of (2) the sum of the concentrations of the chemical species belonging to the group consisting of aromatic hydrocarbons, and (3) the sum of the concentrations of the chemical species belonging to the group consisting of alkynes. It is a process.

In the analysis step S1200, the absorbance calculation unit 191b is based on the light detected by the line sensor 160 (a) a common absorption region that is absorbed by chemical species belonging to the group consisting of alkane and alkene, and (b) from the aromatic hydrocarbon. Absorbance is calculated for each of the common absorption region absorbed by the chemical species belonging to the group and (c) the common absorption region absorbed by the chemical species belonging to the group consisting of the alkyne.
Further, in the analysis step S1200, the concentration calculation unit 191c calculates “alkane based on“ (a) absorbance in a common absorption region absorbed by chemical species belonging to the group consisting of alkane and alkene ”calculated by the absorbance calculation unit 191b. And the sum of the concentrations of chemical species belonging to the group consisting of alkene ”, and“ aromatic carbonization based on “(b) absorbance of a common absorption region absorbed by chemical species belonging to the group consisting of aromatic hydrocarbons”. The sum of the concentrations of the chemical species belonging to the group consisting of hydrogen is calculated, and the “chemistry belonging to the group consisting of alkynes” is calculated based on “(c) the absorbance of the common absorption region absorbed by the chemical species belonging to the group consisting of alkynes”. Calculate the sum of the seed concentrations.

As described above, an embodiment of the hydrocarbon concentration measuring method according to the present invention is as follows.
(A) a common absorption region absorbed by chemical species belonging to the group consisting of alkane and alkene, (b) common absorption region absorbed by chemical species belonging to the group consisting of aromatic hydrocarbons, and (c ) Irradiation / detection step S1100 for irradiating light in a wavelength band including a common absorption region absorbed by a chemical species belonging to the group consisting of alkynes, and detecting light irradiated to the measurement target gas;
Based on the light detected in the irradiation / detection step S1100, (a) a common absorption region absorbed by chemical species belonging to the group consisting of alkanes and alkenes, and (b) chemical species belonging to the group consisting of aromatic hydrocarbons are absorbed. And (c) the absorbance for each of the common absorption regions absorbed by the chemical species belonging to the group consisting of alkynes, and (1) based on the absorbance, (1) belongs to the group consisting of alkanes and alkenes An analysis step S1200 for calculating a sum of concentrations of chemical species, (2) a sum of concentrations of chemical species belonging to the group consisting of aromatic hydrocarbons, and (3) a sum of concentrations of chemical species belonging to the group consisting of alkynes;
It comprises.
By configuring in this way, there is no delay in response to changes in the concentration and composition of the gas to be measured, and it is possible to measure hydrocarbon concentration in real time, ensuring measurement responsiveness. It is.
In addition, when the concentration or composition of the gas to be measured changes, the sum of the concentrations of chemical species that absorb light in the common absorption region (that is, chemical species belonging to the group corresponding to the common absorption region) is accurately calculated. Is possible.

  In this example, the sum of the concentrations of chemical species was calculated for each of (a) a group consisting of alkane and alkene, (b) a group consisting of aromatic hydrocarbons, and (c) a group consisting of alkynes. The total hydrocarbon concentration is calculated as the sum of the calculation results, but the present invention is not limited to this, and (a) a group consisting of alkanes and alkenes, (b) a group consisting of aromatic hydrocarbons, (c) Among the group consisting of alkynes, the target gas is irradiated with light having a wavelength including an absorption region corresponding to a part of the group, and chemical species belonging to the corresponding group are detected based on the absorbance of the detected light in the absorption region. It may be configured to calculate only the sum of the densities.

Further, the common absorption region in one embodiment of the hydrocarbon concentration measurement method according to the present invention is:
The wavelength corresponding to the C—H stretching vibration mode of the chemical species group consisting of (a) alkane and alkene, (b) the chemical species group consisting of aromatic hydrocarbons, and (c) the chemical species group consisting of alkynes, respectively. Is included.
By configuring in this way, it is possible to measure the sum of the concentrations of the chemical species belonging to each of the above groups with good responsiveness and accuracy.
In the present embodiment, the measurement target gas is irradiated with light in a wavelength band that includes all absorption regions corresponding to the three groups. However, the present invention is not limited to this, and any of the above three groups may be used. It is good also as a structure which irradiates the measurement object gas with the light containing the wavelength corresponding to CH stretching mode of any one or any two groups, and measures the sum of the density | concentration of the chemical species which belongs to a corresponding group.

An embodiment of the hydrocarbon concentration measuring method according to the present invention is as follows:
(A) a wavelength corresponding to a C-H stretching vibration mode of the group consisting of alkanes and alkenes is less 2800 cm ^-1 or 3000 cm ^-1 in terms of wavenumber,
(B) a wavelength corresponding to a C-H stretching vibration mode of the group consisting of aromatic hydrocarbons is below 3000 cm ^-1 or 3200 cm ^-1 in terms of wavenumber,
(C) The wavelength corresponding to the C—H stretching vibration mode of the group consisting of alkynes is 3200 cm ⁻¹ or more and 3400 cm ⁻¹ or less in terms of wave number.
By configuring in this way, it is possible to measure the sum of the concentrations of the chemical species belonging to each of the above groups with good responsiveness and accuracy.

The figure which shows the 1st Example of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the experimental installation provided with the 1st Example of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the result of the responsiveness confirmation experiment of the hydrocarbon concentration measurement by the 1st Example of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the result of the measurement accuracy confirmation experiment of the hydrocarbon concentration measurement by the 1st Example of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which similarly shows the result of the measurement precision confirmation experiment of the hydrocarbon concentration measurement by the 1st Example of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the 2nd Example of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the 3rd Example of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows 4th Example of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the 5th Example of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the 6th Example of the hydrocarbon concentration measuring apparatus which concerns on this invention. The figure which shows the 7th Example of the hydrocarbon concentration measuring apparatus which concerns on this invention. The flowchart which shows one Embodiment of the hydrocarbon concentration measuring method which concerns on this invention. The figure which shows the example of the composition analysis result of the fuel supplied to a motor vehicle engine. The figure which shows the example of the composition analysis result of the exhaust gas in an engine exit. The figure which shows the example of the composition analysis result of the exhaust gas in a catalyst exit. The figure which shows the absorption spectrum of the chemical species contained in exhaust gas. The figure which similarly shows the absorption spectrum of the chemical species contained in exhaust gas. The figure which similarly shows the absorption spectrum of the chemical species contained in exhaust gas. The figure which similarly shows the absorption spectrum of the chemical species contained in exhaust gas. The figure which similarly shows the absorption spectrum of the chemical species contained in exhaust gas. The figure which similarly shows the absorption spectrum of the chemical species contained in exhaust gas. The figure which similarly shows the absorption spectrum of the chemical species contained in exhaust gas. The figure which similarly shows the absorption spectrum of the chemical species contained in exhaust gas. IR-Abs. The figure which shows the calculation procedure of ratio. Composition ratio based on FID-GC and IR-Abs. The figure which shows the relationship with ratio. Composition ratio based on FID-GC and IR-Abs. The figure which shows the relationship with ratio. The figure which shows the measurement result of the hydrocarbon density | concentration in exhaust gas by the conventional HC meter and the conventional THC meter, and the relationship of an engine speed.

Explanation of symbols

100 Hydrocarbon concentration measuring device (first embodiment)
130 Infrared irradiation device (irradiation unit)
160 Line sensor (detection unit)
190 Analysis device (analysis unit)

Claims (9)

An irradiation unit configured to irradiate a gas containing a hydrocarbon composed of one or more chemical species with light in a wavelength band including an absorption region common to the one or more chemical species;
A detection unit for detecting light irradiated to the gas by the irradiation unit;
Analysis that calculates the absorbance of the common absorption region based on the light detected by the detection unit, and calculates the sum of the concentrations of chemical species that absorb light in the wavelength band of the common absorption region based on the absorbance And
A hydrocarbon concentration measuring apparatus comprising: The common absorption region is
The hydrocarbon concentration measuring apparatus according to claim 1, comprising a wavelength corresponding to at least one C—H stretching vibration mode of a group consisting of alkane and alkene, a group consisting of aromatic hydrocarbons, and a group consisting of alkynes. The wavelength corresponding to the C-H stretching vibration mode of the group consisting of alkanes and alkenes is less 2800 cm ^-1 or 3000 cm ^-1 in terms of wavenumber,
The wavelength corresponding to the C-H stretching vibration mode of the group consisting of aromatic hydrocarbons is below 3000 cm ^-1 or 3200 cm ^-1 in terms of wavenumber,
3. The hydrocarbon concentration measuring apparatus according to claim 2, wherein a wavelength corresponding to a C—H stretching vibration mode of the alkyne group is 3200 cm ⁻¹ or more and 3400 cm ⁻¹ or less in terms of wave number. A gas introduction container having an internal space capable of introducing a gas containing hydrocarbons composed of one or a plurality of chemical species, provided in an intermediate portion of an optical path of light irradiated by the irradiation unit and detected by the detection unit; ,
An irradiation side window that is provided in the gas introduction container and transmits the light irradiated by the irradiation unit to the internal space;
A detection-side window that is provided in the gas introduction container and transmits the light guided to the internal space from the irradiation-side window and guides it to the outside;
The hydrocarbon concentration measuring device according to any one of claims 1 to 3, further comprising: a gas introduction unit including: Arranged between the irradiation part and the gas containing hydrocarbons composed of one or more chemical species, alternately the state where the light from the irradiation part is irradiated to the gas and the state where the gas is not irradiated A chopper section to be switched,
A signal processing circuit that removes a noise component included in the light detected by the detection unit based on a signal indicating the switching operation of the chopper unit and the light detected by the detection unit;
The hydrocarbon concentration measuring apparatus according to any one of claims 1 to 4, further comprising: The detector is an optical detector;
6. The light-emitting device according to claim 1, further comprising a spectroscopic unit configured to divide the light applied to the gas containing the hydrocarbon including the single or plural chemical species for each wavelength and irradiate the optical detector. The hydrocarbon concentration measuring device according to item. Irradiation / detection for irradiating a gas containing a hydrocarbon composed of one or more chemical species with light in a wavelength band including an absorption region common to the one or more chemical species, and detecting the light emitted to the gas Process,
The absorbance of the common absorption region is calculated based on the light detected in the irradiation / detection step, and the sum of the concentrations of chemical species that absorb light in the wavelength band of the common absorption region is calculated based on the absorbance. An analysis process to
A hydrocarbon concentration measuring method comprising: The common absorption region is
The hydrocarbon concentration measuring method according to claim 7, comprising a wavelength corresponding to at least one C—H stretching vibration mode of a group consisting of alkane and alkene, a group consisting of aromatic hydrocarbons, and a group consisting of alkynes. The wavelength corresponding to the C-H stretching vibration mode of the group consisting of alkanes and alkenes is less 2800 cm ^-1 or 3000 cm ^-1 in terms of wavenumber,
The wavelength corresponding to the C-H stretching vibration mode of the group consisting of aromatic hydrocarbons is below 3000 cm ^-1 or 3200 cm ^-1 in terms of wavenumber,
The method for measuring a hydrocarbon concentration according to claim 8, wherein the wavelength corresponding to the C—H stretching vibration mode of the alkyne group is 3200 cm ⁻¹ or more and 3400 cm ⁻¹ or less in terms of wave number.

Images